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sqlite-utils/sqlite_utils/db.py
Simon Willison 0ec0180405 add_foreign_key() on_delete= and on_update= parameters, closes #530 
table.add_foreign_key() now accepts on_delete= and on_update= to
create foreign keys with ON DELETE/ON UPDATE actions:

    table.add_foreign_key("author_id", "authors", "id", on_delete="CASCADE")

Works for compound foreign keys too.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-05 15:49:20 -07:00

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from .utils import (
chunks,
hash_record,
sqlite3,
OperationalError,
suggest_column_types,
types_for_column_types,
column_affinity,
progressbar,
find_spatialite,
)
import binascii
from collections import namedtuple
from dataclasses import dataclass, field
from collections.abc import Mapping
import contextlib
import datetime
import decimal
import importlib
import inspect
import itertools
import json
import os
import pathlib
import re
import secrets
from sqlite_fts4 import rank_bm25
import textwrap
from typing import (
cast,
Any,
Callable,
Dict,
Generator,
Iterable,
Sequence,
Set,
Type,
Union,
Optional,
List,
Tuple,
)
import uuid
from sqlite_utils.plugins import ensure_plugins_loaded, pm
try:
iterdump = importlib.import_module("sqlite_dump").iterdump
except ImportError:
iterdump = None
SQLITE_MAX_VARS = 999
_quote_fts_re = re.compile(r'\s+|(".*?")')
_virtual_table_using_re = re.compile(
r"""
^ # Start of string
\s*CREATE\s+VIRTUAL\s+TABLE\s+ # CREATE VIRTUAL TABLE
(
'(?P<squoted_table>[^']*(?:''[^']*)*)' | # single quoted name
"(?P<dquoted_table>[^"]*(?:""[^"]*)*)" | # double quoted name
`(?P<backtick_table>[^`]+)` | # `backtick` quoted name
\[(?P<squarequoted_table>[^\]]+)\] | # [...] quoted name
(?P<identifier> # SQLite non-quoted identifier
[A-Za-z_\u0080-\uffff] # \u0080-\uffff = "any character larger than u007f"
[A-Za-z_\u0080-\uffff0-9\$]* # zero-or-more alphanemuric or $
)
)
\s+(IF\s+NOT\s+EXISTS\s+)? # IF NOT EXISTS (optional)
USING\s+(?P<using>\w+) # for example USING FTS5
""",
re.VERBOSE | re.IGNORECASE,
)
def quote_identifier(identifier: str) -> str:
"""
Quote an identifier (table name, column name, etc.) using double quotes.
Double quotes inside the identifier are escaped by doubling them.
"""
return '"{}"'.format(identifier.replace('"', '""'))
pd: Any = None
try:
pd = importlib.import_module("pandas")
except ImportError:
pd = None
np: Any = None
try:
np = importlib.import_module("numpy")
except ImportError:
np = None
Column = namedtuple(
"Column", ("cid", "name", "type", "notnull", "default_value", "is_pk")
)
Column.__doc__ = """
Describes a SQLite column returned by the :attr:`.Table.columns` property.
``cid``
Column index
``name``
Column name
``type``
Column type
``notnull``
Does the column have a ``not null`` constraint
``default_value``
Default value for this column
``is_pk``
Is this column part of the primary key
"""
ColumnDetails = namedtuple(
"ColumnDetails",
(
"table",
"column",
"total_rows",
"num_null",
"num_blank",
"num_distinct",
"most_common",
"least_common",
),
)
ColumnDetails.__doc__ = """
Summary information about a column, see :ref:`python_api_analyze_column`.
``table``
The name of the table
``column``
The name of the column
``total_rows``
The total number of rows in the table
``num_null``
The number of rows for which this column is null
``num_blank``
The number of rows for which this column is blank (the empty string)
``num_distinct``
The number of distinct values in this column
``most_common``
The ``N`` most common values as a list of ``(value, count)`` tuples, or ``None`` if the table consists entirely of distinct values
``least_common``
The ``N`` least common values as a list of ``(value, count)`` tuples, or ``None`` if the table is entirely distinct
or if the number of distinct values is less than N (since they will already have been returned in ``most_common``)
"""
@dataclass(order=True)
class ForeignKey:
"""
A foreign key defined on a table.
For single-column foreign keys ``column`` and ``other_column`` hold the
column names, and ``columns``/``other_columns`` are one-item tuples.
For compound (multi-column) foreign keys ``column`` and ``other_column``
are ``None`` - use ``columns`` and ``other_columns`` instead, and check
``is_compound``.
``on_delete`` and ``on_update`` hold the foreign key actions, e.g.
``"CASCADE"`` - ``"NO ACTION"`` if not set.
Prior to sqlite-utils 4.0 this was a ``namedtuple`` and could be unpacked
or indexed as ``(table, column, other_table, other_column)``. It is now a
dataclass - access its fields by name instead.
"""
table: str
# column/other_column are None for compound keys, which would break
# ordering against str values - comparison uses columns/other_columns
column: Optional[str] = field(compare=False)
other_table: str
other_column: Optional[str] = field(compare=False)
columns: Tuple[str, ...] = ()
other_columns: Tuple[str, ...] = ()
is_compound: bool = False
on_delete: str = "NO ACTION"
on_update: str = "NO ACTION"
def __post_init__(self):
# Populate columns/other_columns for single-column foreign keys,
# normalizing any lists to tuples
if self.columns:
self.columns = tuple(self.columns)
else:
self.columns = (self.column,) if self.column is not None else ()
if self.other_columns:
self.other_columns = tuple(self.other_columns)
else:
self.other_columns = (
(self.other_column,) if self.other_column is not None else ()
)
def _fk_actions_sql(fk: ForeignKey) -> str:
"ON UPDATE/ON DELETE clauses for a foreign key, or an empty string."
actions = ""
if fk.on_update and fk.on_update != "NO ACTION":
actions += " ON UPDATE {}".format(fk.on_update)
if fk.on_delete and fk.on_delete != "NO ACTION":
actions += " ON DELETE {}".format(fk.on_delete)
return actions
Index = namedtuple("Index", ("seq", "name", "unique", "origin", "partial", "columns"))
XIndex = namedtuple("XIndex", ("name", "columns"))
XIndexColumn = namedtuple(
"XIndexColumn", ("seqno", "cid", "name", "desc", "coll", "key")
)
Trigger = namedtuple("Trigger", ("name", "table", "sql"))
class TransformError(Exception):
pass
# A single column name, or a tuple of columns for a compound foreign key
ForeignKeyColumns = Union[str, Tuple[str, ...], List[str]]
# (table, column(s), other_table, other_column(s))
ForeignKeyTuple = Tuple[str, ForeignKeyColumns, str, ForeignKeyColumns]
ForeignKeyIndicator = Union[
str,
ForeignKey,
Tuple[ForeignKeyColumns, str],
Tuple[ForeignKeyColumns, str, ForeignKeyColumns],
ForeignKeyTuple,
]
ForeignKeysType = Union[Iterable[ForeignKeyIndicator], List[ForeignKeyIndicator]]
class Default:
pass
DEFAULT = Default()
Tracer = Callable[[str, Optional[Union[Sequence[Any], Dict[str, Any]]]], None]
def _iter_complete_sql_statements(sql: str) -> Generator[str, None, None]:
statement = []
for char in sql:
statement.append(char)
statement_sql = "".join(statement).strip()
if statement_sql and sqlite3.complete_statement(statement_sql):
yield statement_sql
statement = []
statement_sql = "".join(statement).strip()
if statement_sql:
yield statement_sql
COLUMN_TYPE_MAPPING: Dict[Any, str] = {
float: "REAL",
int: "INTEGER",
bool: "INTEGER",
str: "TEXT",
dict: "TEXT",
tuple: "TEXT",
list: "TEXT",
bytes.__class__: "BLOB",
bytes: "BLOB",
memoryview: "BLOB",
datetime.datetime: "TEXT",
datetime.date: "TEXT",
datetime.time: "TEXT",
datetime.timedelta: "TEXT",
decimal.Decimal: "REAL",
None.__class__: "TEXT",
uuid.UUID: "TEXT",
# SQLite explicit types
"TEXT": "TEXT",
"INTEGER": "INTEGER",
"FLOAT": "FLOAT",
"REAL": "REAL",
"BLOB": "BLOB",
"text": "TEXT",
"str": "TEXT",
"integer": "INTEGER",
"int": "INTEGER",
"float": "REAL",
"real": "REAL",
"blob": "BLOB",
"bytes": "BLOB",
}
# If numpy is available, add more types
if np:
try:
COLUMN_TYPE_MAPPING.update(
{
np.int8: "INTEGER",
np.int16: "INTEGER",
np.int32: "INTEGER",
np.int64: "INTEGER",
np.uint8: "INTEGER",
np.uint16: "INTEGER",
np.uint32: "INTEGER",
np.uint64: "INTEGER",
np.float16: "REAL",
np.float32: "REAL",
np.float64: "REAL",
}
)
except AttributeError:
# https://github.com/simonw/sqlite-utils/issues/632
pass
# If pandas is available, add more types
if pd:
COLUMN_TYPE_MAPPING.update({pd.Timestamp: "TEXT"}) # type: ignore
class AlterError(Exception):
"Error altering table"
class NoObviousTable(Exception):
"Could not tell which table this operation refers to"
class NoTable(Exception):
"Specified table does not exist"
class NoView(Exception):
"Specified view does not exist"
class BadPrimaryKey(Exception):
"Table does not have a single obvious primary key"
class NotFoundError(Exception):
"Record not found"
class PrimaryKeyRequired(Exception):
"Primary key needs to be specified"
class InvalidColumns(Exception):
"Specified columns do not exist"
class TransactionError(Exception):
"Operation cannot be performed while a transaction is open"
class DescIndex(str):
pass
class BadMultiValues(Exception):
"With multi=True code must return a Python dictionary"
def __init__(self, values: object) -> None:
self.values = values
_COUNTS_TABLE_CREATE_SQL = """
CREATE TABLE IF NOT EXISTS "{}"(
"table" TEXT PRIMARY KEY,
count INTEGER DEFAULT 0
);
""".strip()
_TRANSACTION_CONTROL_KEYWORDS = {
"BEGIN",
"COMMIT",
"END",
"ROLLBACK",
"SAVEPOINT",
"RELEASE",
}
# Statements that never return rows and cannot run inside (or would break
# out of) the savepoint guard used by query()
_QUERY_REJECTED_KEYWORDS = _TRANSACTION_CONTROL_KEYWORDS | {
"VACUUM",
"ATTACH",
"DETACH",
}
def _first_keyword(sql: str) -> str:
"""
Return the first keyword of a SQL statement, uppercased, skipping any
leading whitespace and ``--`` or ``/* ... */`` comments - the only
things SQLite's tokenizer allows before the first token. Returns an
empty string if there is no leading keyword.
"""
i, n = 0, len(sql)
while i < n:
if sql[i].isspace():
i += 1
elif sql.startswith("--", i):
newline = sql.find("\n", i)
if newline == -1:
return ""
i = newline + 1
elif sql.startswith("/*", i):
end = sql.find("*/", i + 2)
if end == -1:
return ""
i = end + 2
else:
break
j = i
while j < n and (sql[j].isalpha() or sql[j] == "_"):
j += 1
return sql[i:j].upper()
class Database:
"""
Wrapper for a SQLite database connection that adds a variety of useful utility methods.
To create an instance::
# create data.db file, or open existing:
db = Database("data.db")
# Create an in-memory database:
dB = Database(memory=True)
:param filename_or_conn: String path to a file, or a ``pathlib.Path`` object, or a
``sqlite3`` connection
:param memory: set to ``True`` to create an in-memory database
:param memory_name: creates a named in-memory database that can be shared across multiple connections
:param recreate: set to ``True`` to delete and recreate a file database (**dangerous**)
:param recursive_triggers: defaults to ``True``, which sets ``PRAGMA recursive_triggers=on;`` -
set to ``False`` to avoid setting this pragma
:param tracer: set a tracer function (``print`` works for this) which will be called with
``sql, parameters`` every time a SQL query is executed
:param use_counts_table: set to ``True`` to use a cached counts table, if available. See
:ref:`python_api_cached_table_counts`
:param use_old_upsert: set to ``True`` to force the older upsert implementation. See
:ref:`python_api_old_upsert`
:param strict: Apply STRICT mode to all created tables (unless overridden)
"""
_counts_table_name = "_counts"
use_counts_table = False
conn: sqlite3.Connection
def __init__(
self,
filename_or_conn: Optional[Union[str, pathlib.Path, sqlite3.Connection]] = None,
memory: bool = False,
memory_name: Optional[str] = None,
recreate: bool = False,
recursive_triggers: bool = True,
tracer: Optional[Tracer] = None,
use_counts_table: bool = False,
execute_plugins: bool = True,
use_old_upsert: bool = False,
strict: bool = False,
):
self.memory_name = None
self.memory = False
self.use_old_upsert = use_old_upsert
if not (
(filename_or_conn is not None and (not memory and not memory_name))
or (filename_or_conn is None and (memory or memory_name))
):
raise ValueError("Either specify a filename_or_conn or pass memory=True")
if memory_name:
uri = "file:{}?mode=memory&cache=shared".format(memory_name)
self.conn = sqlite3.connect(
uri,
uri=True,
check_same_thread=False,
)
self.memory = True
self.memory_name = memory_name
elif memory or filename_or_conn == ":memory:":
self.conn = sqlite3.connect(":memory:")
self.memory = True
elif isinstance(filename_or_conn, (str, pathlib.Path)):
if recreate and os.path.exists(filename_or_conn):
try:
os.remove(filename_or_conn)
except OSError:
# Avoid mypy and __repr__ errors, see:
# https://github.com/simonw/sqlite-utils/issues/503
self.conn = sqlite3.connect(":memory:")
raise
self.conn = sqlite3.connect(str(filename_or_conn))
else:
if recreate:
raise ValueError("recreate cannot be used with connections, only paths")
self.conn = cast(sqlite3.Connection, filename_or_conn)
# Python 3.12+ autocommit=True/False connections make commit()
# and rollback() behave differently, silently breaking the
# transaction handling used by every write method
autocommit = getattr(self.conn, "autocommit", None)
if autocommit is not None and autocommit != getattr(
sqlite3, "LEGACY_TRANSACTION_CONTROL", -1
):
raise TransactionError(
"sqlite-utils requires a connection that uses the default "
"transaction handling - connections created with "
"autocommit=True or autocommit=False are not supported"
)
self._tracer: Optional[Tracer] = tracer
if recursive_triggers:
self.execute("PRAGMA recursive_triggers=on;")
self._registered_functions: set = set()
self.use_counts_table = use_counts_table
if execute_plugins:
ensure_plugins_loaded()
pm.hook.prepare_connection(conn=self.conn)
self.strict = strict
def __enter__(self) -> "Database":
return self
def __exit__(
self,
exc_type: Optional[Type[BaseException]],
exc_val: Optional[BaseException],
exc_tb: Optional[object],
) -> None:
self.close()
def close(self) -> None:
"Close the SQLite connection, and the underlying database file"
self.conn.close()
@contextlib.contextmanager
def atomic(self) -> Generator["Database", None, None]:
"""
Context manager for wrapping multiple database operations in a transaction.
Nested blocks use SQLite savepoints.
"""
if self.conn.in_transaction:
savepoint = "sqlite_utils_{}".format(secrets.token_hex(16))
self.conn.execute("SAVEPOINT {};".format(savepoint))
try:
yield self
except BaseException:
self.conn.execute("ROLLBACK TO SAVEPOINT {};".format(savepoint))
self.conn.execute("RELEASE SAVEPOINT {};".format(savepoint))
raise
else:
self.conn.execute("RELEASE SAVEPOINT {};".format(savepoint))
else:
self.conn.execute("BEGIN")
try:
yield self
except BaseException:
self.conn.execute("ROLLBACK")
raise
else:
try:
self.conn.execute("COMMIT")
except BaseException:
self.conn.execute("ROLLBACK")
raise
def begin(self) -> None:
"""
Start a transaction with ``BEGIN``, taking manual control of transaction
handling. End it by calling :meth:`commit` or :meth:`rollback`.
Raises ``sqlite3.OperationalError`` if a transaction is already open.
Most code should use the :meth:`atomic` context manager instead, which
commits and rolls back automatically. See :ref:`python_api_transactions`.
"""
self.execute("BEGIN")
def commit(self) -> None:
"""
Commit the current transaction. Does nothing if no transaction is open.
"""
if self.conn.in_transaction:
self.conn.execute("COMMIT")
def rollback(self) -> None:
"""
Roll back the current transaction, discarding its changes. Does nothing
if no transaction is open.
"""
if self.conn.in_transaction:
self.conn.execute("ROLLBACK")
@contextlib.contextmanager
def ensure_autocommit_off(self) -> Generator[None, None, None]:
"""
Ensure autocommit is off for this database connection.
Example usage::
with db.ensure_autocommit_off():
# do stuff here
This will reset to the previous autocommit state at the end of the block.
"""
old_isolation_level = self.conn.isolation_level
try:
self.conn.isolation_level = None
yield
finally:
self.conn.isolation_level = old_isolation_level
@contextlib.contextmanager
def tracer(
self, tracer: Optional[Tracer] = None
) -> Generator["Database", None, None]:
"""
Context manager to temporarily set a tracer function - all executed SQL queries will
be passed to this.
The tracer function should accept two arguments: ``sql`` and ``parameters``
Example usage::
with db.tracer(print):
db["creatures"].insert({"name": "Cleo"})
See :ref:`python_api_tracing`.
:param tracer: Callable accepting ``sql`` and ``parameters`` arguments
"""
prev_tracer = self._tracer
self._tracer = tracer or cast(Tracer, print)
try:
yield self
finally:
self._tracer = prev_tracer
def __getitem__(self, table_name: str) -> Union["Table", "View"]:
"""
``db[name]`` returns a :class:`.Table` object for the table with the specified name,
or a :class:`.View` object if the name matches an existing SQL view.
If neither exists yet, a table is assumed - it will be created the first
time data is inserted into it.
:param table_name: The name of the table or view
"""
if table_name in self.view_names():
return self.view(table_name)
return self.table(table_name)
def __repr__(self) -> str:
return "<Database {}>".format(self.conn)
def register_function(
self,
fn: Optional[Callable] = None,
deterministic: bool = False,
replace: bool = False,
name: Optional[str] = None,
) -> Optional[Callable[[Callable], Callable]]:
"""
``fn`` will be made available as a function within SQL, with the same name and number
of arguments. Can be used as a decorator::
@db.register_function
def upper(value):
return str(value).upper()
The decorator can take arguments::
@db.register_function(deterministic=True, replace=True)
def upper(value):
return str(value).upper()
See :ref:`python_api_register_function`.
:param fn: Function to register
:param deterministic: set ``True`` for functions that always returns the same output for a given input
:param replace: set ``True`` to replace an existing function with the same name - otherwise throw an error
:param name: name of the SQLite function - if not specified, the Python function name will be used
"""
def register(fn: Callable) -> Callable:
fn_name = name or fn.__name__ # type: ignore
arity = len(inspect.signature(fn).parameters)
if not replace and (fn_name, arity) in self._registered_functions:
return fn
kwargs: Dict[str, bool] = {}
registered = False
if deterministic:
# Try this, but fall back if sqlite3.NotSupportedError
try:
self.conn.create_function(
fn_name, arity, fn, **dict(kwargs, deterministic=True)
)
registered = True
except sqlite3.NotSupportedError:
pass
if not registered:
self.conn.create_function(fn_name, arity, fn, **kwargs)
self._registered_functions.add((fn_name, arity))
return fn
if fn is None:
return register
else:
register(fn)
return None
def register_fts4_bm25(self) -> None:
"Register the ``rank_bm25(match_info)`` function used for calculating relevance with SQLite FTS4."
self.register_function(rank_bm25, deterministic=True, replace=True)
def attach(self, alias: str, filepath: Union[str, pathlib.Path]) -> None:
"""
Attach another SQLite database file to this connection with the specified alias, equivalent to::
ATTACH DATABASE 'filepath.db' AS alias
:param alias: Alias name to use
:param filepath: Path to SQLite database file on disk
"""
attach_sql = """
ATTACH DATABASE '{}' AS {};
""".format(
str(pathlib.Path(filepath).resolve()), quote_identifier(alias)
).strip()
self.execute(attach_sql)
def query(
self, sql: str, params: Optional[Union[Sequence, Dict[str, Any]]] = None
) -> Generator[dict, None, None]:
"""
Execute ``sql`` and return an iterable of dictionaries representing each row.
The SQL is executed as soon as this method is called - the resulting rows
are then fetched lazily as the returned iterable is iterated over. A
row-returning write such as ``INSERT ... RETURNING`` takes effect
immediately, even if the results are never iterated.
:param sql: SQL query to execute
:param params: Parameters to use in that query - an iterable for ``where id = ?``
parameters, or a dictionary for ``where id = :id``
:raises ValueError: if the SQL statement does not return rows - use
:meth:`execute` for those statements instead. The rejected statement
is rolled back, so it has no effect on the database
"""
message = (
"query() can only be used with SQL that returns rows - "
"use execute() for other statements"
)
keyword = _first_keyword(sql)
if keyword in _QUERY_REJECTED_KEYWORDS:
# None of these return rows - reject them without executing anything
raise ValueError(message)
if self._tracer:
self._tracer(sql, params)
args: tuple = (params,) if params is not None else ()
if keyword == "PRAGMA":
# Some PRAGMA statements refuse to run inside a transaction, so
# execute these without the savepoint guard used below. Some
# adapters open an implicit transaction before comment-prefixed
# PRAGMAs, so temporarily use driver autocommit when it is safe.
if self.conn.in_transaction:
cursor = self.conn.execute(sql, *args)
else:
with self.ensure_autocommit_off():
cursor = self.conn.execute(sql, *args)
if cursor.description is None:
raise ValueError(message)
keys = [d[0] for d in cursor.description]
return (dict(zip(keys, row)) for row in cursor)
# Execute inside a savepoint, so a statement that turns out not to
# return rows can be rolled back before the ValueError is raised
self.conn.execute('SAVEPOINT "sqlite_utils_query"')
released = False
try:
cursor = self.conn.execute(sql, *args)
if cursor.description is None:
raise ValueError(message)
keys = [d[0] for d in cursor.description]
try:
self.conn.execute('RELEASE "sqlite_utils_query"')
released = True
except sqlite3.OperationalError:
# The savepoint cannot be released while a write statement is
# still executing - this is INSERT ... RETURNING or similar,
# with unfetched rows. Fetch them so the write completes, then
# release again - committing the write immediately, unless an
# outer transaction is open
fetched = cursor.fetchall()
self.conn.execute('RELEASE "sqlite_utils_query"')
released = True
return (dict(zip(keys, row)) for row in fetched)
return (dict(zip(keys, row)) for row in cursor)
finally:
if not released:
# An error occurred - undo anything the statement changed
self.conn.execute('ROLLBACK TO "sqlite_utils_query"')
self.conn.execute('RELEASE "sqlite_utils_query"')
def execute(
self, sql: str, parameters: Optional[Union[Sequence, Dict[str, Any]]] = None
) -> sqlite3.Cursor:
"""
Execute SQL query and return a ``sqlite3.Cursor``.
A write statement - ``INSERT``, ``UPDATE``, ``CREATE TABLE`` and so on -
is committed automatically, unless a transaction is already open, in
which case it becomes part of that transaction. See
:ref:`python_api_transactions`.
:param sql: SQL query to execute
:param parameters: Parameters to use in that query - an iterable for ``where id = ?``
parameters, or a dictionary for ``where id = :id``
"""
if self._tracer:
self._tracer(sql, parameters)
was_in_transaction = self.conn.in_transaction
if parameters is not None:
cursor = self.conn.execute(sql, parameters)
else:
cursor = self.conn.execute(sql)
if (
not was_in_transaction
and self.conn.in_transaction
and cursor.description is None
and _first_keyword(sql) not in _TRANSACTION_CONTROL_KEYWORDS
):
# The statement opened an implicit transaction - commit it, so
# that execute() behaves consistently with the rest of the
# library and identically across connection modes
self.conn.execute("COMMIT")
return cursor
def executescript(self, sql: str) -> sqlite3.Cursor:
"""
Execute multiple SQL statements separated by ; and return the ``sqlite3.Cursor``.
:param sql: SQL to execute
"""
if self._tracer:
self._tracer(sql, None)
return self._executescript(sql)
def _executescript(self, sql: str) -> sqlite3.Cursor:
if self.conn.in_transaction:
cursor = self.conn.cursor()
# avoid sqlite3.executescript()'s implicit commit:
for statement in _iter_complete_sql_statements(sql):
cursor.execute(statement)
return cursor
return self.conn.executescript(sql)
def table(self, table_name: str, **kwargs: Any) -> "Table":
"""
Return a table object, optionally configured with default options.
See :ref:`reference_db_table` for option details.
:param table_name: Name of the table
"""
if table_name in self.view_names():
raise NoTable("Table {} is actually a view".format(table_name))
kwargs.setdefault("strict", self.strict)
return Table(self, table_name, **kwargs)
def view(self, view_name: str) -> "View":
"""
Return a view object.
:param view_name: Name of the view
"""
if view_name not in self.view_names():
if view_name in self.table_names():
raise NoView(
"View {name} does not exist - {name} is a table".format(
name=view_name
)
)
raise NoView("View {} does not exist".format(view_name))
return View(self, view_name)
def quote(self, value: str) -> str:
"""
Apply SQLite string quoting to a value, including wrapping it in single quotes.
:param value: String to quote
"""
# Normally we would use .execute(sql, [params]) for escaping, but
# occasionally that isn't available - most notable when we need
# to include a "... DEFAULT 'value'" in a column definition.
return self.execute(
# Use SQLite itself to correctly escape this string:
"SELECT quote(:value)",
{"value": value},
).fetchone()[0]
def quote_fts(self, query: str) -> str:
"""
Escape special characters in a SQLite full-text search query.
This works by surrounding each token within the query with double
quotes, in order to avoid words like ``NOT`` and ``OR`` having
special meaning as defined by the FTS query syntax here:
https://www.sqlite.org/fts5.html#full_text_query_syntax
If the query has unbalanced ``"`` characters, adds one at end.
:param query: String to escape
"""
if query.count('"') % 2:
query += '"'
bits = _quote_fts_re.split(query)
bits = [b for b in bits if b and b != '""']
return " ".join(
'"{}"'.format(bit) if not bit.startswith('"') else bit for bit in bits
)
def quote_default_value(self, value: str) -> str:
if any(
[
str(value).startswith("'") and str(value).endswith("'"),
str(value).startswith('"') and str(value).endswith('"'),
]
):
return value
if str(value).upper() in ("CURRENT_TIME", "CURRENT_DATE", "CURRENT_TIMESTAMP"):
return value
if str(value).endswith(")"):
# Expr
return "({})".format(value)
return self.quote(value)
def table_names(self, fts4: bool = False, fts5: bool = False) -> List[str]:
"""
List of string table names in this database.
:param fts4: Only return tables that are part of FTS4 indexes
:param fts5: Only return tables that are part of FTS5 indexes
"""
where = ["type = 'table'"]
if fts4:
where.append("sql like '%USING FTS4%'")
if fts5:
where.append("sql like '%USING FTS5%'")
sql = "select name from sqlite_master where {}".format(" AND ".join(where))
return [r[0] for r in self.execute(sql).fetchall()]
def view_names(self) -> List[str]:
"List of string view names in this database."
return [
r[0]
for r in self.execute(
"select name from sqlite_master where type = 'view'"
).fetchall()
]
@property
def tables(self) -> List["Table"]:
"List of Table objects in this database."
return [self.table(name) for name in self.table_names()]
@property
def views(self) -> List["View"]:
"List of View objects in this database."
return [self.view(name) for name in self.view_names()]
@property
def triggers(self) -> List[Trigger]:
"List of ``(name, table_name, sql)`` tuples representing triggers in this database."
return [
Trigger(*r)
for r in self.execute(
"select name, tbl_name, sql from sqlite_master where type = 'trigger'"
).fetchall()
]
@property
def triggers_dict(self) -> Dict[str, str]:
"A ``{trigger_name: sql}`` dictionary of triggers in this database."
return {trigger.name: trigger.sql for trigger in self.triggers}
@property
def schema(self) -> str:
"SQL schema for this database."
sqls = []
for row in self.execute(
"select sql from sqlite_master where sql is not null"
).fetchall():
sql = row[0]
if not sql.strip().endswith(";"):
sql += ";"
sqls.append(sql)
return "\n".join(sqls)
@property
def supports_strict(self) -> bool:
"Does this database support STRICT mode?"
if not hasattr(self, "_supports_strict"):
try:
table_name = "t{}".format(secrets.token_hex(16))
with self.atomic():
self.conn.execute(
"create table {} (name text) strict".format(table_name)
)
self.conn.execute("drop table {}".format(table_name))
self._supports_strict = True
except Exception:
self._supports_strict = False
return self._supports_strict
@property
def supports_on_conflict(self) -> bool:
# SQLite's upsert is implemented as INSERT INTO ... ON CONFLICT DO ...
if not hasattr(self, "_supports_on_conflict"):
table_name = "t{}".format(secrets.token_hex(16))
try:
with self.atomic():
self.conn.execute(
"create table {} (id integer primary key, name text)".format(
table_name
)
)
self.conn.execute(
"insert into {} (id, name) values (1, 'one')".format(table_name)
)
self.conn.execute(
(
"insert into {} (id, name) values (1, 'two') "
"on conflict do update set name = 'two'"
).format(table_name)
)
self._supports_on_conflict = True
except Exception:
self._supports_on_conflict = False
finally:
self.conn.execute("drop table if exists {}".format(table_name))
return self._supports_on_conflict
@property
def sqlite_version(self) -> Tuple[int, ...]:
"Version of SQLite, as a tuple of integers for example ``(3, 36, 0)``."
row = self.execute("select sqlite_version()").fetchall()[0]
return tuple(map(int, row[0].split(".")))
@property
def journal_mode(self) -> str:
"""
Current ``journal_mode`` of this database.
https://www.sqlite.org/pragma.html#pragma_journal_mode
"""
return self.execute("PRAGMA journal_mode;").fetchone()[0]
def enable_wal(self) -> None:
"""
Sets ``journal_mode`` to ``'wal'`` to enable Write-Ahead Log mode.
:raises TransactionError: if called while a transaction is open - the
journal mode can only be changed outside of a transaction
"""
if self.journal_mode != "wal":
self._ensure_no_open_transaction("enable_wal()")
with self.ensure_autocommit_off():
self.execute("PRAGMA journal_mode=wal;")
def disable_wal(self) -> None:
"""
Sets ``journal_mode`` back to ``'delete'`` to disable Write-Ahead Log mode.
:raises TransactionError: if called while a transaction is open - the
journal mode can only be changed outside of a transaction
"""
if self.journal_mode != "delete":
self._ensure_no_open_transaction("disable_wal()")
with self.ensure_autocommit_off():
self.execute("PRAGMA journal_mode=delete;")
def _ensure_no_open_transaction(self, operation: str) -> None:
# Changing journal mode assigns conn.isolation_level, which commits
# any open transaction as a side effect - breaking the rollback
# guarantee of atomic() and of user-managed transactions
if self.conn.in_transaction:
raise TransactionError(
"{} cannot be used while a transaction is open".format(operation)
)
def _ensure_counts_table(self) -> None:
with self.atomic():
self.execute(_COUNTS_TABLE_CREATE_SQL.format(self._counts_table_name))
def enable_counts(self) -> None:
"""
Enable trigger-based count caching for every table in the database, see
:ref:`python_api_cached_table_counts`.
"""
self._ensure_counts_table()
for table in self.tables:
if (
table.virtual_table_using is None
and table.name != self._counts_table_name
):
table.enable_counts()
self.use_counts_table = True
def cached_counts(self, tables: Optional[Iterable[str]] = None) -> Dict[str, int]:
"""
Return ``{table_name: count}`` dictionary of cached counts for specified tables, or
all tables if ``tables`` not provided.
:param tables: Subset list of tables to return counts for.
"""
sql = 'select "table", count from {}'.format(self._counts_table_name)
tables_list = list(tables) if tables else None
if tables_list:
sql += ' where "table" in ({})'.format(", ".join("?" for _ in tables_list))
try:
return {r[0]: r[1] for r in self.execute(sql, tables_list).fetchall()}
except OperationalError:
return {}
def reset_counts(self) -> None:
"Re-calculate cached counts for tables."
tables = [table for table in self.tables if table.has_counts_triggers]
with self.atomic():
self._ensure_counts_table()
counts_table = self.table(self._counts_table_name)
counts_table.delete_where()
counts_table.insert_all(
{"table": table.name, "count": table.execute_count()}
for table in tables
)
def execute_returning_dicts(
self, sql: str, params: Optional[Union[Sequence, Dict[str, Any]]] = None
) -> List[dict]:
return list(self.query(sql, params))
def resolve_foreign_keys(
self, name: str, foreign_keys: ForeignKeysType
) -> List[ForeignKey]:
"""
Given a list of differing foreign_keys definitions, return a list of
fully resolved ForeignKey() named tuples.
:param name: Name of table that foreign keys are being defined for
:param foreign_keys: List of foreign keys, each of which can be a
string, a ForeignKey() object, a tuple of (column, other_table),
or a tuple of (column, other_table, other_column), or a tuple of
(table, column, other_table, other_column). For compound foreign
keys the column elements can be tuples of column names, e.g.
(("campus_name", "dept_code"), "departments") or
(("campus_name", "dept_code"), "departments", ("campus_name", "dept_code"))
"""
table = self.table(name)
if all(isinstance(fk, ForeignKey) for fk in foreign_keys):
return cast(List[ForeignKey], foreign_keys)
if all(isinstance(fk, str) for fk in foreign_keys):
# It's a list of columns
fks = []
for column in foreign_keys:
column = cast(str, column)
other_table = table.guess_foreign_table(column)
other_column = table.guess_foreign_column(other_table)
fks.append(ForeignKey(name, column, other_table, other_column))
return fks
if not all(isinstance(fk, (tuple, list)) for fk in foreign_keys):
raise ValueError("foreign_keys= should be a list of tuples")
fks = []
for tuple_or_list in cast(Iterable[Sequence[Any]], foreign_keys):
if len(tuple_or_list) == 4:
if tuple_or_list[0] != name:
raise ValueError(
"First item in {} should have been {}".format(
tuple_or_list, name
)
)
tuple_or_list = tuple_or_list[1:]
if len(tuple_or_list) not in (2, 3):
raise ValueError(
"foreign_keys= should be a list of tuple pairs or triples"
)
column_or_columns = tuple_or_list[0]
other_table = tuple_or_list[1]
if isinstance(column_or_columns, (list, tuple)):
# Compound foreign key
columns = tuple(column_or_columns)
if len(tuple_or_list) == 3:
if not isinstance(tuple_or_list[2], (list, tuple)):
raise ValueError(
"Compound foreign key {} should reference a tuple "
"of other columns".format(tuple(tuple_or_list))
)
other_columns = tuple(tuple_or_list[2])
else:
# Guess the compound primary key of the other table
other_columns = tuple(self.table(other_table).pks)
if len(columns) != len(other_columns):
raise ValueError(
"Compound foreign key {} should have the same number "
"of columns on both sides".format(tuple(tuple_or_list))
)
if len(columns) == 1:
# Single-column key passed as a one-item list
fks.append(
ForeignKey(name, columns[0], other_table, other_columns[0])
)
else:
fks.append(
ForeignKey(
name,
None,
other_table,
None,
columns=columns,
other_columns=other_columns,
is_compound=True,
)
)
elif len(tuple_or_list) == 3:
fks.append(
ForeignKey(name, column_or_columns, other_table, tuple_or_list[2])
)
else:
# Guess the primary key
fks.append(
ForeignKey(
name,
column_or_columns,
other_table,
table.guess_foreign_column(other_table),
)
)
return fks
def create_table_sql(
self,
name: str,
columns: Dict[str, Any],
pk: Optional[Any] = None,
foreign_keys: Optional[ForeignKeysType] = None,
column_order: Optional[List[str]] = None,
not_null: Optional[Iterable[str]] = None,
defaults: Optional[Dict[str, Any]] = None,
hash_id: Optional[str] = None,
hash_id_columns: Optional[Iterable[str]] = None,
extracts: Optional[Union[Dict[str, str], List[str]]] = None,
if_not_exists: bool = False,
strict: bool = False,
) -> str:
"""
Returns the SQL ``CREATE TABLE`` statement for creating the specified table.
:param name: Name of table
:param columns: Dictionary mapping column names to their types, for example ``{"name": str, "age": int}``
:param pk: String name of column to use as a primary key, or a tuple of strings for a compound primary key covering multiple columns
:param foreign_keys: List of foreign key definitions for this table
:param column_order: List specifying which columns should come first
:param not_null: List of columns that should be created as ``NOT NULL``
:param defaults: Dictionary specifying default values for columns
:param hash_id: Name of column to be used as a primary key containing a hash of the other columns
:param hash_id_columns: List of columns to be used when calculating the hash ID for a row
:param extracts: List or dictionary of columns to be extracted during inserts, see :ref:`python_api_extracts`
:param if_not_exists: Use ``CREATE TABLE IF NOT EXISTS``
:param strict: Apply STRICT mode to table
"""
if hash_id_columns and (hash_id is None):
hash_id = "id"
foreign_keys = self.resolve_foreign_keys(name, foreign_keys or [])
# Compound foreign keys are rendered as table-level constraints;
# single-column ones as inline REFERENCES on their column
foreign_keys_by_column = {
fk.column: fk for fk in foreign_keys if not fk.is_compound
}
# any extracts will be treated as integer columns with a foreign key
extracts = resolve_extracts(extracts)
for extract_column, extract_table in extracts.items():
if isinstance(extract_column, tuple):
assert False
# Ensure other table exists
if not self[extract_table].exists():
self.create_table(extract_table, {"id": int, "value": str}, pk="id")
columns[extract_column] = int
foreign_keys_by_column[extract_column] = ForeignKey(
name, extract_column, extract_table, "id"
)
# Soundness check not_null, and defaults if provided
not_null = not_null or set()
defaults = defaults or {}
if not columns:
raise ValueError("Tables must have at least one column")
if not all(n in columns for n in not_null):
raise ValueError(
"not_null set {} includes items not in columns {}".format(
repr(not_null), repr(set(columns.keys()))
)
)
if not all(n in columns for n in defaults):
raise ValueError(
"defaults set {} includes items not in columns {}".format(
repr(set(defaults)), repr(set(columns.keys()))
)
)
column_items = list(columns.items())
if column_order is not None:
def sort_key(p):
return column_order.index(p[0]) if p[0] in column_order else 999
column_items.sort(key=sort_key)
if hash_id:
column_items.insert(0, (hash_id, str))
pk = hash_id
# Soundness check foreign_keys point to existing tables
for fk in foreign_keys:
for other_column in fk.other_columns:
if fk.other_table == name and columns.get(other_column):
continue
if other_column != "rowid" and not any(
c for c in self[fk.other_table].columns if c.name == other_column
):
raise AlterError(
"No such column: {}.{}".format(fk.other_table, other_column)
)
column_defs = []
# ensure pk is a tuple
single_pk = None
if isinstance(pk, list) and len(pk) == 1 and isinstance(pk[0], str):
pk = pk[0]
if isinstance(pk, str):
single_pk = pk
if pk not in [c[0] for c in column_items]:
column_items.insert(0, (pk, int))
for column_name, column_type in column_items:
column_extras = []
if column_name == single_pk:
column_extras.append("PRIMARY KEY")
if column_name in not_null:
column_extras.append("NOT NULL")
if column_name in defaults and defaults[column_name] is not None:
column_extras.append(
"DEFAULT {}".format(self.quote_default_value(defaults[column_name]))
)
if column_name in foreign_keys_by_column:
fk = foreign_keys_by_column[column_name]
column_extras.append(
"REFERENCES {}({}){}".format(
quote_identifier(fk.other_table),
quote_identifier(cast(str, fk.other_column)),
_fk_actions_sql(fk),
)
)
column_type_str = COLUMN_TYPE_MAPPING[column_type]
# Special case for strict tables to map FLOAT to REAL
# Refs https://github.com/simonw/sqlite-utils/issues/644
if strict and column_type_str == "FLOAT":
column_type_str = "REAL"
column_defs.append(
" {} {column_type}{column_extras}".format(
quote_identifier(column_name),
column_type=column_type_str,
column_extras=(
(" " + " ".join(column_extras)) if column_extras else ""
),
)
)
extra_pk = ""
if single_pk is None and pk and len(pk) > 1:
extra_pk = ",\n PRIMARY KEY ({pks})".format(
pks=", ".join([quote_identifier(p) for p in pk])
)
# Compound foreign keys become table-level FOREIGN KEY constraints
column_names = [c[0] for c in column_items]
for fk in foreign_keys:
if not fk.is_compound:
continue
missing = [c for c in fk.columns if c not in column_names]
if missing:
raise AlterError(
"No such column: {}".format(", ".join(sorted(missing)))
)
column_defs.append(
" FOREIGN KEY ({columns}) REFERENCES {other_table}({other_columns}){actions}".format(
columns=", ".join(quote_identifier(c) for c in fk.columns),
other_table=quote_identifier(fk.other_table),
other_columns=", ".join(
quote_identifier(c) for c in fk.other_columns
),
actions=_fk_actions_sql(fk),
)
)
columns_sql = ",\n".join(column_defs)
sql = """CREATE TABLE {if_not_exists}{table} (
{columns_sql}{extra_pk}
){strict};
""".format(
if_not_exists="IF NOT EXISTS " if if_not_exists else "",
table=quote_identifier(name),
columns_sql=columns_sql,
extra_pk=extra_pk,
strict=" STRICT" if strict and self.supports_strict else "",
)
return sql
def create_table(
self,
name: str,
columns: Dict[str, Any],
pk: Optional[Any] = None,
foreign_keys: Optional[ForeignKeysType] = None,
column_order: Optional[List[str]] = None,
not_null: Optional[Iterable[str]] = None,
defaults: Optional[Dict[str, Any]] = None,
hash_id: Optional[str] = None,
hash_id_columns: Optional[Iterable[str]] = None,
extracts: Optional[Union[Dict[str, str], List[str]]] = None,
if_not_exists: bool = False,
replace: bool = False,
ignore: bool = False,
transform: bool = False,
strict: bool = False,
) -> "Table":
"""
Create a table with the specified name and the specified ``{column_name: type}`` columns.
See :ref:`python_api_explicit_create`.
:param name: Name of table
:param columns: Dictionary mapping column names to their types, for example ``{"name": str, "age": int}``
:param pk: String name of column to use as a primary key, or a tuple of strings for a compound primary key covering multiple columns
:param foreign_keys: List of foreign key definitions for this table
:param column_order: List specifying which columns should come first
:param not_null: List of columns that should be created as ``NOT NULL``
:param defaults: Dictionary specifying default values for columns
:param hash_id: Name of column to be used as a primary key containing a hash of the other columns
:param hash_id_columns: List of columns to be used when calculating the hash ID for a row
:param extracts: List or dictionary of columns to be extracted during inserts, see :ref:`python_api_extracts`
:param if_not_exists: Use ``CREATE TABLE IF NOT EXISTS``
:param replace: Drop and replace table if it already exists
:param ignore: Silently do nothing if table already exists
:param transform: If table already exists transform it to fit the specified schema
:param strict: Apply STRICT mode to table
"""
# Transform table to match the new definition if table already exists:
if self[name].exists():
if ignore:
return self.table(name)
elif replace:
self[name].drop()
if transform and self[name].exists():
table = self.table(name)
should_transform = False
# First add missing columns and figure out columns to drop
existing_columns = table.columns_dict
missing_columns = dict(
(col_name, col_type)
for col_name, col_type in columns.items()
if col_name not in existing_columns
)
columns_to_drop = [
column for column in existing_columns if column not in columns
]
if missing_columns:
for col_name, col_type in missing_columns.items():
table.add_column(col_name, col_type)
if missing_columns or columns_to_drop or columns != existing_columns:
should_transform = True
# Do we need to change the column order?
if (
column_order
and list(existing_columns)[: len(column_order)] != column_order
):
should_transform = True
# Has the primary key changed?
current_pks = table.pks
desired_pk = None
if isinstance(pk, str):
desired_pk = [pk]
elif pk:
desired_pk = list(pk)
if desired_pk and current_pks != desired_pk:
should_transform = True
# Any not-null changes?
current_not_null = {c.name for c in table.columns if c.notnull}
desired_not_null = set(not_null) if not_null else set()
if current_not_null != desired_not_null:
should_transform = True
# How about defaults?
if defaults and defaults != table.default_values:
should_transform = True
# Only run .transform() if there is something to do
if should_transform:
table.transform(
types=columns,
drop=columns_to_drop,
column_order=column_order,
not_null=not_null,
defaults=defaults,
pk=pk,
)
return table
sql = self.create_table_sql(
name=name,
columns=columns,
pk=pk,
foreign_keys=foreign_keys,
column_order=column_order,
not_null=not_null,
defaults=defaults,
hash_id=hash_id,
hash_id_columns=hash_id_columns,
extracts=extracts,
if_not_exists=if_not_exists,
strict=strict,
)
self.execute(sql)
return self.table(
name,
pk=pk,
foreign_keys=foreign_keys,
column_order=column_order,
not_null=not_null,
defaults=defaults,
hash_id=hash_id,
hash_id_columns=hash_id_columns,
)
def rename_table(self, name: str, new_name: str) -> None:
"""
Rename a table.
:param name: Current table name
:param new_name: Name to rename it to
"""
self.execute(
"ALTER TABLE {} RENAME TO {}".format(
quote_identifier(name), quote_identifier(new_name)
)
)
def create_view(
self, name: str, sql: str, ignore: bool = False, replace: bool = False
) -> "Database":
"""
Create a new SQL view with the specified name - ``sql`` should start with ``SELECT ...``.
:param name: Name of the view
:param sql: SQL ``SELECT`` query to use for this view.
:param ignore: Set to ``True`` to do nothing if a view with this name already exists
:param replace: Set to ``True`` to replace the view if one with this name already exists
"""
if ignore and replace:
raise ValueError("Use one or the other of ignore/replace, not both")
create_sql = "CREATE VIEW {name} AS {sql}".format(
name=quote_identifier(name), sql=sql
)
if ignore or replace:
# Does view exist already?
if name in self.view_names():
if ignore:
return self
elif replace:
# If SQL is the same, do nothing
if create_sql == self[name].schema:
return self
self[name].drop()
self.execute(create_sql)
return self
def m2m_table_candidates(self, table: str, other_table: str) -> List[str]:
"""
Given two table names returns the name of tables that could define a
many-to-many relationship between those two tables, based on having
foreign keys to both of the provided tables.
:param table: Table name
:param other_table: Other table name
"""
candidates = []
tables = {table, other_table}
for table_obj in self.tables:
# Does it have foreign keys to both table and other_table?
has_fks_to = {fk.other_table for fk in table_obj.foreign_keys}
if has_fks_to.issuperset(tables):
candidates.append(table_obj.name)
return candidates
def add_foreign_keys(
self, foreign_keys: Iterable[Union[ForeignKey, ForeignKeyTuple]]
) -> None:
"""
See :ref:`python_api_add_foreign_keys`.
:param foreign_keys: A list of ``(table, column, other_table, other_column)``
tuples - for compound foreign keys, ``column`` and ``other_column`` can
be tuples of column names
"""
# foreign_keys is a list of explicit 4-tuples
if not all(
isinstance(fk, ForeignKey)
or (isinstance(fk, (list, tuple)) and len(fk) == 4)
for fk in foreign_keys
):
raise ValueError(
"foreign_keys must be a list of 4-tuples, "
"(table, column, other_table, other_column)"
)
foreign_keys_to_create: List[ForeignKey] = []
# Verify that all tables and columns exist
for fk in foreign_keys:
if isinstance(fk, ForeignKey):
fk_object = fk
else:
table, column_or_columns, other_table, other_column_or_columns = fk
# Compound foreign keys use tuples of columns
columns = (
(column_or_columns,)
if isinstance(column_or_columns, str)
else tuple(column_or_columns)
)
other_columns = (
(other_column_or_columns,)
if isinstance(other_column_or_columns, str)
else tuple(other_column_or_columns)
)
if len(columns) == 1:
fk_object = ForeignKey(
table, columns[0], other_table, other_columns[0]
)
else:
fk_object = ForeignKey(
table,
None,
other_table,
None,
columns=columns,
other_columns=other_columns,
is_compound=True,
)
table = fk_object.table
columns = fk_object.columns
other_table = fk_object.other_table
other_columns = fk_object.other_columns
if not self.table(table).exists():
raise AlterError("No such table: {}".format(table))
table_obj = self.table(table)
for column in columns:
if column not in table_obj.columns_dict:
raise AlterError("No such column: {} in {}".format(column, table))
if not self[other_table].exists():
raise AlterError("No such other_table: {}".format(other_table))
for other_column in other_columns:
if (
other_column != "rowid"
and other_column not in self[other_table].columns_dict
):
raise AlterError(
"No such other_column: {} in {}".format(
other_column, other_table
)
)
# We will silently skip foreign keys that exist already
if not any(
fk
for fk in table_obj.foreign_keys
if fk.columns == columns
and fk.other_table == other_table
and fk.other_columns == other_columns
):
foreign_keys_to_create.append(fk_object)
# Group them by table
by_table: Dict[str, List[ForeignKey]] = {}
for fk_object in foreign_keys_to_create:
by_table.setdefault(fk_object.table, []).append(fk_object)
for table, fks in by_table.items():
self.table(table).transform(add_foreign_keys=fks)
if not self.conn.in_transaction:
self.vacuum()
def index_foreign_keys(self) -> None:
"Create indexes for every foreign key column on every table in the database."
for table_name in self.table_names():
table = self.table(table_name)
existing_indexes = {tuple(i.columns) for i in table.indexes}
for fk in table.foreign_keys:
# A compound foreign key gets a single composite index
if fk.columns not in existing_indexes:
table.create_index(fk.columns, find_unique_name=True)
existing_indexes.add(fk.columns)
def vacuum(self) -> None:
"Run a SQLite ``VACUUM`` against the database."
self.execute("VACUUM;")
def analyze(self, name: Optional[str] = None) -> None:
"""
Run ``ANALYZE`` against the entire database or a named table or index.
:param name: Run ``ANALYZE`` against this specific named table or index
"""
sql = "ANALYZE"
if name is not None:
sql += " {}".format(quote_identifier(name))
self.execute(sql)
def iterdump(self) -> Generator[str, None, None]:
"A sequence of strings representing a SQL dump of the database"
if iterdump:
yield from iterdump(self.conn)
else:
try:
yield from self.conn.iterdump()
except AttributeError:
raise AttributeError(
"conn.iterdump() not found - try pip install sqlite-dump"
)
def init_spatialite(self, path: Optional[str] = None) -> bool:
"""
The ``init_spatialite`` method will load and initialize the SpatiaLite extension.
The ``path`` argument should be an absolute path to the compiled extension, which
can be found using ``find_spatialite``.
Returns ``True`` if SpatiaLite was successfully initialized.
.. code-block:: python
from sqlite_utils.db import Database
from sqlite_utils.utils import find_spatialite
db = Database("mydb.db")
db.init_spatialite(find_spatialite())
If you've installed SpatiaLite somewhere unexpected (for testing an alternate version, for example)
you can pass in an absolute path:
.. code-block:: python
from sqlite_utils.db import Database
from sqlite_utils.utils import find_spatialite
db = Database("mydb.db")
db.init_spatialite("./local/mod_spatialite.dylib")
:param path: Path to SpatiaLite module on disk
"""
if path is None:
path = find_spatialite()
if path is None:
raise OSError("Could not find SpatiaLite extension")
self.conn.enable_load_extension(True)
self.conn.load_extension(path)
# Initialize SpatiaLite if not yet initialized
if "spatial_ref_sys" in self.table_names():
return False
cursor = self.execute("select InitSpatialMetadata(1)")
result = cursor.fetchone()
return result and bool(result[0])
class Queryable:
db: "Database"
name: str
def exists(self) -> bool:
"Does this table or view exist yet?"
return False
def __init__(self, db: "Database", name: str) -> None:
self.db = db
self.name = name
def count_where(
self,
where: Optional[str] = None,
where_args: Optional[Union[Sequence, Dict[str, Any]]] = None,
) -> int:
"""
Executes ``SELECT count(*) FROM table WHERE ...`` and returns a count.
:param where: SQL where fragment to use, for example ``id > ?``
:param where_args: Parameters to use with that fragment - an iterable for ``id > ?``
parameters, or a dictionary for ``id > :id``
"""
sql = "select count(*) from {}".format(quote_identifier(self.name))
if where is not None:
sql += " where " + where
return self.db.execute(sql, where_args or []).fetchone()[0]
def execute_count(self) -> int:
# Backwards compatibility, see https://github.com/simonw/sqlite-utils/issues/305#issuecomment-890713185
return self.count_where()
@property
def count(self) -> int:
"A count of the rows in this table or view."
return self.count_where()
@property
def rows(self) -> Generator[Dict[str, Any], None, None]:
"Iterate over every dictionaries for each row in this table or view."
return self.rows_where()
def rows_where(
self,
where: Optional[str] = None,
where_args: Optional[Union[Sequence, Dict[str, Any]]] = None,
order_by: Optional[str] = None,
select: str = "*",
limit: Optional[int] = None,
offset: Optional[int] = None,
) -> Generator[Dict[str, Any], None, None]:
"""
Iterate over every row in this table or view that matches the specified where clause.
Returns each row as a dictionary. See :ref:`python_api_rows` for more details.
:param where: SQL where fragment to use, for example ``id > ?``
:param where_args: Parameters to use with that fragment - an iterable for ``id > ?``
parameters, or a dictionary for ``id > :id``
:param order_by: Column or fragment of SQL to order by
:param select: Comma-separated list of columns to select - defaults to ``*``
:param limit: Integer number of rows to limit to
:param offset: Integer for SQL offset
"""
if not self.exists():
return
sql = "select {} from {}".format(select, quote_identifier(self.name))
if where is not None:
sql += " where " + where
if order_by is not None:
sql += " order by " + order_by
if limit is not None:
sql += " limit {}".format(limit)
if offset is not None:
sql += " offset {}".format(offset)
cursor = self.db.execute(sql, where_args or [])
columns = [c[0] for c in cursor.description]
for row in cursor:
yield dict(zip(columns, row))
def pks_and_rows_where(
self,
where: Optional[str] = None,
where_args: Optional[Union[Sequence, Dict[str, Any]]] = None,
order_by: Optional[str] = None,
limit: Optional[int] = None,
offset: Optional[int] = None,
) -> Generator[Tuple[Any, Dict[str, Any]], None, None]:
"""
Like ``.rows_where()`` but returns ``(pk, row)`` pairs - ``pk`` can be a single value or tuple.
:param where: SQL where fragment to use, for example ``id > ?``
:param where_args: Parameters to use with that fragment - an iterable for ``id > ?``
parameters, or a dictionary for ``id > :id``
:param order_by: Column or fragment of SQL to order by
:param select: Comma-separated list of columns to select - defaults to ``*``
:param limit: Integer number of rows to limit to
:param offset: Integer for SQL offset
"""
column_names = [column.name for column in self.columns]
pks = [column.name for column in self.columns if column.is_pk]
if not pks:
column_names.insert(0, "rowid")
pks = ["rowid"]
select = ",".join(quote_identifier(column_name) for column_name in column_names)
for row in self.rows_where(
select=select,
where=where,
where_args=where_args,
order_by=order_by,
limit=limit,
offset=offset,
):
row_pk = tuple(row[pk] for pk in pks)
if len(row_pk) == 1:
row_pk = row_pk[0]
yield row_pk, row
@property
def columns(self) -> List["Column"]:
"List of :ref:`Columns <reference_db_other_column>` representing the columns in this table or view."
if not self.exists():
return []
rows = self.db.execute(
"PRAGMA table_info({})".format(quote_identifier(self.name))
).fetchall()
return [Column(*row) for row in rows]
@property
def columns_dict(self) -> Dict[str, Any]:
"``{column_name: python-type}`` dictionary representing columns in this table or view."
return {column.name: column_affinity(column.type) for column in self.columns}
@property
def schema(self) -> str:
"SQL schema for this table or view."
return self.db.execute(
"select sql from sqlite_master where name = ?", (self.name,)
).fetchone()[0]
class Table(Queryable):
"""
Tables should usually be initialized using the ``db.table(table_name)`` or
``db[table_name]`` methods.
The following optional parameters can be passed to ``db.table(table_name, ...)``:
:param db: Provided by ``db.table(table_name)``
:param name: Provided by ``db.table(table_name)``
:param pk: Name of the primary key column, or tuple of columns
:param foreign_keys: List of foreign key definitions
:param column_order: List of column names in the order they should be in the table
:param not_null: List of columns that cannot be null
:param defaults: Dictionary of column names and default values
:param batch_size: Integer number of rows to insert at a time
:param hash_id: Name of a column to create and use as a primary key, where the
value of that primary key is derived from a hash of the row values
:param hash_id_columns: List of columns to use for the hash_id
:param alter: If True, automatically alter the table if it doesn't match the schema
:param ignore: If True, ignore rows that already exist when inserting
:param replace: If True, replace rows that already exist when inserting
:param extracts: Dictionary or list of column names to extract into a separate table on inserts
:param conversions: Dictionary of column names and conversion functions
:param columns: Dictionary of column names to column types
:param strict: If True, apply STRICT mode to table
"""
#: The ``rowid`` of the last inserted, updated or selected row.
last_rowid: Optional[int] = None
#: The primary key of the last inserted, updated or selected row.
last_pk: Optional[Any] = None
def __init__(
self,
db: Database,
name: str,
pk: Optional[Any] = None,
foreign_keys: Optional[ForeignKeysType] = None,
column_order: Optional[List[str]] = None,
not_null: Optional[Iterable[str]] = None,
defaults: Optional[Dict[str, Any]] = None,
batch_size: int = 100,
hash_id: Optional[str] = None,
hash_id_columns: Optional[Iterable[str]] = None,
alter: bool = False,
ignore: bool = False,
replace: bool = False,
extracts: Optional[Union[Dict[str, str], List[str]]] = None,
conversions: Optional[dict] = None,
columns: Optional[Dict[str, Any]] = None,
strict: bool = False,
):
super().__init__(db, name)
self._defaults = dict(
pk=pk,
foreign_keys=foreign_keys,
column_order=column_order,
not_null=not_null,
defaults=defaults,
batch_size=batch_size,
hash_id=hash_id,
hash_id_columns=hash_id_columns,
alter=alter,
ignore=ignore,
replace=replace,
extracts=extracts,
conversions=conversions or {},
columns=columns,
strict=strict,
)
def __repr__(self) -> str:
return "<Table {}{}>".format(
self.name,
(
" (does not exist yet)"
if not self.exists()
else " ({})".format(", ".join(c.name for c in self.columns))
),
)
@property
def count(self) -> int:
"Count of the rows in this table - optionally from the table count cache, if configured."
if self.db.use_counts_table:
counts = self.db.cached_counts([self.name])
if counts:
return next(iter(counts.values()))
return self.count_where()
def exists(self) -> bool:
return self.name in self.db.table_names()
@property
def pks(self) -> List[str]:
"Primary key columns for this table."
names = [column.name for column in self.columns if column.is_pk]
if not names:
names = ["rowid"]
return names
@property
def use_rowid(self) -> bool:
"Does this table use ``rowid`` for its primary key (no other primary keys are specified)?"
return not any(column for column in self.columns if column.is_pk)
def get(self, pk_values: Union[list, tuple, str, int]) -> dict:
"""
Return row (as dictionary) for the specified primary key.
Raises ``sqlite_utils.db.NotFoundError`` if a matching row cannot be found.
:param pk_values: A single value, or a tuple of values for tables that have a compound primary key
"""
if not isinstance(pk_values, (list, tuple)):
pk_values = [pk_values]
pks = self.pks
last_pk = pk_values[0] if len(pks) == 1 else pk_values
if len(pks) != len(pk_values):
raise NotFoundError(
"Need {} primary key value{}".format(
len(pks), "" if len(pks) == 1 else "s"
)
)
wheres = ["{} = ?".format(quote_identifier(pk_name)) for pk_name in pks]
rows = self.rows_where(" and ".join(wheres), pk_values)
try:
row = list(rows)[0]
self.last_pk = last_pk
return row
except IndexError:
raise NotFoundError
@property
def foreign_keys(self) -> List["ForeignKey"]:
"""
List of foreign keys defined on this table.
Compound (multi-column) foreign keys are returned as a single
``ForeignKey`` with ``is_compound=True`` and populated
``columns``/``other_columns`` lists.
"""
# PRAGMA foreign_key_list returns one row per column, grouped by "id"
# with "seq" giving the column order within a compound foreign key.
by_id: Dict[int, list] = {}
for row in self.db.execute(
"PRAGMA foreign_key_list({})".format(quote_identifier(self.name))
).fetchall():
if row is not None:
id, seq, table_name, from_, to_, on_update, on_delete, match = row
by_id.setdefault(id, []).append(
(seq, table_name, from_, to_, on_update, on_delete)
)
fks = []
for id in sorted(by_id):
rows = sorted(by_id[id]) # order columns by seq
other_table = rows[0][1]
columns = tuple(row[2] for row in rows)
other_columns = tuple(row[3] for row in rows)
if all(c is None for c in other_columns):
# "REFERENCES other_table" with no columns - the pragma
# returns None, meaning the other table's primary key
other_table_pks = tuple(self.db.table(other_table).pks)
if len(other_table_pks) == len(columns):
other_columns = other_table_pks
is_compound = len(rows) > 1
fks.append(
ForeignKey(
table=self.name,
column=None if is_compound else columns[0],
other_table=other_table,
other_column=None if is_compound else other_columns[0],
columns=columns,
other_columns=other_columns,
is_compound=is_compound,
on_update=rows[0][4],
on_delete=rows[0][5],
)
)
return fks
@property
def virtual_table_using(self) -> Optional[str]:
"Type of virtual table, or ``None`` if this is not a virtual table."
match = _virtual_table_using_re.match(self.schema)
if match is None:
return None
return match.groupdict()["using"].upper()
@property
def indexes(self) -> List[Index]:
"List of indexes defined on this table."
sql = 'PRAGMA index_list("{}")'.format(self.name)
indexes = []
for row in self.db.execute_returning_dicts(sql):
index_name = row["name"]
index_name_quoted = (
'"{}"'.format(index_name)
if not index_name.startswith('"')
else index_name
)
column_sql = "PRAGMA index_info({})".format(index_name_quoted)
columns = []
for seqno, cid, name in self.db.execute(column_sql).fetchall():
columns.append(name)
row["columns"] = columns
# These columns may be missing on older SQLite versions:
for key, default in {"origin": "c", "partial": 0}.items():
if key not in row:
row[key] = default
indexes.append(Index(**row))
return indexes
@property
def xindexes(self) -> List[XIndex]:
"List of indexes defined on this table using the more detailed ``XIndex`` format."
sql = 'PRAGMA index_list("{}")'.format(self.name)
indexes = []
for row in self.db.execute_returning_dicts(sql):
index_name = row["name"]
index_name_quoted = (
'"{}"'.format(index_name)
if not index_name.startswith('"')
else index_name
)
column_sql = "PRAGMA index_xinfo({})".format(index_name_quoted)
index_columns = []
for info in self.db.execute(column_sql).fetchall():
index_columns.append(XIndexColumn(*info))
indexes.append(XIndex(index_name, index_columns))
return indexes
@property
def triggers(self) -> List[Trigger]:
"List of triggers defined on this table."
return [
Trigger(*r)
for r in self.db.execute(
"select name, tbl_name, sql from sqlite_master where type = 'trigger'"
" and tbl_name = ?",
(self.name,),
).fetchall()
]
@property
def triggers_dict(self) -> Dict[str, str]:
"``{trigger_name: sql}`` dictionary of triggers defined on this table."
return {trigger.name: trigger.sql for trigger in self.triggers}
@property
def default_values(self) -> Dict[str, Any]:
"``{column_name: default_value}`` dictionary of default values for columns in this table."
return {
column.name: _decode_default_value(column.default_value)
for column in self.columns
if column.default_value is not None
}
@property
def strict(self) -> bool:
"Is this a STRICT table?"
table_suffix = self.schema.split(")")[-1].strip().upper()
table_options = [bit.strip() for bit in table_suffix.split(",")]
return "STRICT" in table_options
def create(
self,
columns: Dict[str, Any],
pk: Optional[Any] = DEFAULT,
foreign_keys: Union[Optional[ForeignKeysType], Default] = DEFAULT,
column_order: Union[Optional[List[str]], Default] = DEFAULT,
not_null: Union[Optional[Iterable[str]], Default] = DEFAULT,
defaults: Union[Optional[Dict[str, Any]], Default] = DEFAULT,
hash_id: Union[Optional[str], Default] = DEFAULT,
hash_id_columns: Union[Optional[Iterable[str]], Default] = DEFAULT,
extracts: Union[Optional[Union[Dict[str, str], List[str]]], Default] = DEFAULT,
if_not_exists: bool = False,
replace: bool = False,
ignore: bool = False,
transform: bool = False,
strict: Union[bool, Default] = DEFAULT,
) -> "Table":
"""
Create a table with the specified columns.
See :ref:`python_api_explicit_create` for full details.
:param columns: Dictionary mapping column names to their types, for example ``{"name": str, "age": int}``
:param pk: String name of column to use as a primary key, or a tuple of strings for a compound primary key covering multiple columns
:param foreign_keys: List of foreign key definitions for this table
:param column_order: List specifying which columns should come first
:param not_null: List of columns that should be created as ``NOT NULL``
:param defaults: Dictionary specifying default values for columns
:param hash_id: Name of column to be used as a primary key containing a hash of the other columns
:param hash_id_columns: List of columns to be used when calculating the hash ID for a row
:param extracts: List or dictionary of columns to be extracted during inserts, see :ref:`python_api_extracts`
:param if_not_exists: Use ``CREATE TABLE IF NOT EXISTS``
:param replace: Drop and replace table if it already exists
:param ignore: Silently do nothing if table already exists
:param transform: If table already exists transform it to fit the specified schema
:param strict: Apply STRICT mode to table
"""
# Resolve defaults from _defaults (issue #655)
pk = self.value_or_default("pk", pk)
foreign_keys = self.value_or_default("foreign_keys", foreign_keys)
column_order = self.value_or_default("column_order", column_order)
not_null = self.value_or_default("not_null", not_null)
defaults = self.value_or_default("defaults", defaults)
hash_id = self.value_or_default("hash_id", hash_id)
hash_id_columns = self.value_or_default("hash_id_columns", hash_id_columns)
extracts = self.value_or_default("extracts", extracts)
strict = self.value_or_default("strict", strict)
# Store configuration in _defaults for subsequent operations (issue #655)
# Don't store pk if hash_id is set, since pk is derived from hash_id in that case
if pk is not None and hash_id is None:
self._defaults["pk"] = pk
if foreign_keys is not None:
self._defaults["foreign_keys"] = foreign_keys
if column_order is not None:
self._defaults["column_order"] = column_order
if not_null is not None:
self._defaults["not_null"] = not_null
if defaults is not None:
self._defaults["defaults"] = defaults
if hash_id is not None:
self._defaults["hash_id"] = hash_id
if hash_id_columns is not None:
self._defaults["hash_id_columns"] = hash_id_columns
if extracts is not None:
self._defaults["extracts"] = extracts
if strict:
self._defaults["strict"] = strict
columns = {name: value for (name, value) in columns.items()}
with self.db.atomic():
self.db.create_table(
self.name,
columns,
pk=pk,
foreign_keys=foreign_keys, # type: ignore[arg-type]
column_order=column_order, # type: ignore[arg-type]
not_null=not_null, # type: ignore[arg-type]
defaults=defaults, # type: ignore[arg-type]
hash_id=hash_id, # type: ignore[arg-type]
hash_id_columns=hash_id_columns, # type: ignore[arg-type]
extracts=extracts, # type: ignore[arg-type]
if_not_exists=if_not_exists,
replace=replace,
ignore=ignore,
transform=transform,
strict=strict, # type: ignore[arg-type]
)
return self
def duplicate(self, new_name: str) -> "Table":
"""
Create a duplicate of this table, copying across the schema and all row data.
:param new_name: Name of the new table
"""
if not self.exists():
raise NoTable(f"Table {self.name} does not exist")
with self.db.atomic():
sql = "CREATE TABLE {} AS SELECT * FROM {};".format(
quote_identifier(new_name),
quote_identifier(self.name),
)
self.db.execute(sql)
return self.db.table(new_name)
def transform(
self,
*,
types: Optional[dict] = None,
rename: Optional[dict] = None,
drop: Optional[Iterable] = None,
pk: Optional[Any] = DEFAULT,
not_null: Optional[Iterable[str]] = None,
defaults: Optional[Dict[str, Any]] = None,
drop_foreign_keys: Optional[Iterable[str]] = None,
add_foreign_keys: Optional[ForeignKeysType] = None,
foreign_keys: Optional[ForeignKeysType] = None,
column_order: Optional[List[str]] = None,
keep_table: Optional[str] = None,
) -> "Table":
"""
Apply an advanced alter table, including operations that are not supported by
``ALTER TABLE`` in SQLite itself.
See :ref:`python_api_transform` for full details.
:param types: Columns that should have their type changed, for example ``{"weight": float}``
:param rename: Columns to rename, for example ``{"headline": "title"}``
:param drop: Columns to drop
:param pk: New primary key for the table
:param not_null: Columns to set as ``NOT NULL``
:param defaults: Default values for columns
:param drop_foreign_keys: Foreign key constraints to remove - a column name
drops any foreign key that column participates in, a tuple of column names
drops the compound foreign key with exactly those columns
:param add_foreign_keys: List of foreign keys to add to the table
:param foreign_keys: List of foreign keys to set for the table, replacing any existing foreign keys
:param column_order: List of strings specifying a full or partial column order
to use when creating the table
:param keep_table: If specified, the existing table will be renamed to this and will not be
dropped
"""
if not self.exists():
raise ValueError("Cannot transform a table that doesn't exist yet")
sqls = self.transform_sql(
types=types,
rename=rename,
drop=drop,
pk=pk,
not_null=not_null,
defaults=defaults,
drop_foreign_keys=drop_foreign_keys,
add_foreign_keys=add_foreign_keys,
foreign_keys=foreign_keys,
column_order=column_order,
keep_table=keep_table,
)
pragma_foreign_keys_was_on = bool(
self.db.execute("PRAGMA foreign_keys").fetchone()[0]
)
already_in_transaction = self.db.conn.in_transaction
should_disable_foreign_keys = (
pragma_foreign_keys_was_on and not already_in_transaction
)
should_defer_foreign_keys = (
pragma_foreign_keys_was_on and already_in_transaction
)
defer_foreign_keys_was_on = False
try:
if should_disable_foreign_keys:
self.db.execute("PRAGMA foreign_keys=0;")
elif should_defer_foreign_keys:
defer_foreign_keys_was_on = bool(
self.db.execute("PRAGMA defer_foreign_keys").fetchone()[0]
)
if not defer_foreign_keys_was_on:
self.db.execute("PRAGMA defer_foreign_keys=ON;")
with self.db.atomic():
for sql in sqls:
self.db.execute(sql)
# Run the foreign_key_check before we commit
if pragma_foreign_keys_was_on:
foreign_key_violations = self.db.execute(
"PRAGMA foreign_key_check;"
).fetchall()
if foreign_key_violations:
raise sqlite3.IntegrityError("FOREIGN KEY constraint failed")
finally:
if should_defer_foreign_keys and not defer_foreign_keys_was_on:
self.db.execute("PRAGMA defer_foreign_keys=OFF;")
if should_disable_foreign_keys:
self.db.execute("PRAGMA foreign_keys=1;")
return self
def transform_sql(
self,
*,
types: Optional[dict] = None,
rename: Optional[dict] = None,
drop: Optional[Iterable] = None,
pk: Optional[Any] = DEFAULT,
not_null: Optional[Iterable[str]] = None,
defaults: Optional[Dict[str, Any]] = None,
drop_foreign_keys: Optional[Iterable] = None,
add_foreign_keys: Optional[ForeignKeysType] = None,
foreign_keys: Optional[ForeignKeysType] = None,
column_order: Optional[List[str]] = None,
tmp_suffix: Optional[str] = None,
keep_table: Optional[str] = None,
) -> List[str]:
"""
Return a list of SQL statements that should be executed in order to apply this transformation.
:param types: Columns that should have their type changed, for example ``{"weight": float}``
:param rename: Columns to rename, for example ``{"headline": "title"}``
:param drop: Columns to drop
:param pk: New primary key for the table
:param not_null: Columns to set as ``NOT NULL``
:param defaults: Default values for columns
:param drop_foreign_keys: Foreign key constraints to remove - a column name
drops any foreign key that column participates in, a tuple of column names
drops the compound foreign key with exactly those columns
:param add_foreign_keys: List of foreign keys to add to the table
:param foreign_keys: List of foreign keys to set for the table, replacing any existing foreign keys
:param column_order: List of strings specifying a full or partial column order
to use when creating the table
:param tmp_suffix: Suffix to use for the temporary table name
:param keep_table: If specified, the existing table will be renamed to this and will not be
dropped
"""
types = types or {}
rename = rename or {}
drop = drop or set()
create_table_foreign_keys: List[ForeignKeyIndicator] = []
if foreign_keys is not None:
if add_foreign_keys is not None:
raise ValueError(
"Cannot specify both foreign_keys and add_foreign_keys"
)
if drop_foreign_keys is not None:
raise ValueError(
"Cannot specify both foreign_keys and drop_foreign_keys"
)
create_table_foreign_keys.extend(foreign_keys)
else:
# Construct foreign_keys from current, plus add_foreign_keys, minus drop_foreign_keys
# Bind fresh names here - type checkers do not narrow captured
# variables inside nested functions, so the closures would
# otherwise see the Optional declared types of drop and rename
dropped_columns = drop
renamed_columns = rename
def fk_should_be_dropped(fk: ForeignKey) -> bool:
if drop_foreign_keys is not None:
for spec in drop_foreign_keys:
if isinstance(spec, str):
# A column name matches any foreign key it participates in
if spec in fk.columns:
return True
elif tuple(spec) == fk.columns:
# A tuple/list must match a compound key's columns exactly
return True
# Dropping any of a foreign key's columns drops the whole key
return any(column in dropped_columns for column in fk.columns)
def fk_with_renamed_columns(fk: ForeignKey) -> ForeignKey:
columns = tuple(
renamed_columns.get(column) or column for column in fk.columns
)
if fk.is_compound:
return ForeignKey(
self.name,
None,
fk.other_table,
None,
columns=columns,
other_columns=fk.other_columns,
is_compound=True,
on_delete=fk.on_delete,
on_update=fk.on_update,
)
return ForeignKey(
self.name,
columns[0],
fk.other_table,
fk.other_columns[0],
on_delete=fk.on_delete,
on_update=fk.on_update,
)
create_table_foreign_keys = []
# Copy over old foreign keys, unless we are dropping them
for fk in self.foreign_keys:
if not fk_should_be_dropped(fk):
create_table_foreign_keys.append(fk_with_renamed_columns(fk))
# Add new foreign keys
if add_foreign_keys is not None:
for fk in self.db.resolve_foreign_keys(self.name, add_foreign_keys):
create_table_foreign_keys.append(fk_with_renamed_columns(fk))
new_table_name = "{}_new_{}".format(
self.name, tmp_suffix or os.urandom(6).hex()
)
current_column_pairs = list(self.columns_dict.items())
new_column_pairs = []
copy_from_to = {column: column for column, _ in current_column_pairs}
for name, type_ in current_column_pairs:
type_ = types.get(name) or type_
if name in drop:
del [copy_from_to[name]]
continue
new_name = rename.get(name) or name
new_column_pairs.append((new_name, type_))
copy_from_to[name] = new_name
if pk is DEFAULT:
pks_renamed = tuple(
rename.get(p.name) or p.name for p in self.columns if p.is_pk
)
if len(pks_renamed) == 1:
pk = pks_renamed[0]
else:
pk = pks_renamed
# not_null may be a set or dict, need to convert to a set
create_table_not_null = {
rename.get(c.name) or c.name
for c in self.columns
if c.notnull
if c.name not in drop
}
if isinstance(not_null, dict):
# Remove any columns with a value of False
for key, value in not_null.items():
# Column may have been renamed
key = rename.get(key) or key
if value is False and key in create_table_not_null:
create_table_not_null.remove(key)
else:
create_table_not_null.add(key)
elif isinstance(not_null, set):
create_table_not_null.update((rename.get(k) or k) for k in not_null)
elif not not_null:
pass
else:
raise ValueError(
"not_null must be a dict or a set or None, it was {}".format(
repr(not_null)
)
)
# defaults=
create_table_defaults = {
(rename.get(c.name) or c.name): c.default_value
for c in self.columns
if c.default_value is not None and c.name not in drop
}
if defaults is not None:
create_table_defaults.update(
{rename.get(c) or c: v for c, v in defaults.items()}
)
if column_order is not None:
column_order = [rename.get(col) or col for col in column_order]
sqls = []
sqls.append(
self.db.create_table_sql(
new_table_name,
dict(new_column_pairs),
pk=pk,
not_null=create_table_not_null,
defaults=create_table_defaults,
foreign_keys=create_table_foreign_keys,
column_order=column_order,
strict=self.strict,
).strip()
)
# Copy across data, respecting any renamed columns
new_cols = []
old_cols = []
for from_, to_ in copy_from_to.items():
old_cols.append(from_)
new_cols.append(to_)
# Ensure rowid is copied too
if "rowid" not in new_cols:
new_cols.insert(0, "rowid")
old_cols.insert(0, "rowid")
copy_sql = "INSERT INTO {} ({new_cols})\n SELECT {old_cols} FROM {};".format(
quote_identifier(new_table_name),
quote_identifier(self.name),
old_cols=", ".join(quote_identifier(col) for col in old_cols),
new_cols=", ".join(quote_identifier(col) for col in new_cols),
)
sqls.append(copy_sql)
# Drop (or keep) the old table
if keep_table:
sqls.append(
"ALTER TABLE {} RENAME TO {};".format(
quote_identifier(self.name), quote_identifier(keep_table)
)
)
else:
sqls.append("DROP TABLE {};".format(quote_identifier(self.name)))
# Rename the new one
sqls.append(
"ALTER TABLE {} RENAME TO {};".format(
quote_identifier(new_table_name), quote_identifier(self.name)
)
)
# Re-add existing indexes
for index in self.indexes:
if index.origin != "pk":
index_sql = self.db.execute(
"""SELECT sql FROM sqlite_master WHERE type = 'index' AND name = :index_name;""",
{"index_name": index.name},
).fetchall()[0][0]
if index_sql is None:
raise TransformError(
f"Index '{index.name}' on table '{self.name}' does not have a "
"CREATE INDEX statement. You must manually drop this index prior to running this "
"transformation and manually recreate the new index after running this transformation."
)
if keep_table:
sqls.append(f"DROP INDEX IF EXISTS {quote_identifier(index.name)};")
for col in index.columns:
if col in rename.keys() or col in drop:
raise TransformError(
f"Index '{index.name}' column '{col}' is not in updated table '{self.name}'. "
f"You must manually drop this index prior to running this transformation "
f"and manually recreate the new index after running this transformation. "
f"The original index sql statement is: `{index_sql}`. No changes have been applied to this table."
)
sqls.append(index_sql)
return sqls
def extract(
self,
columns: Union[str, Iterable[str]],
table: Optional[str] = None,
fk_column: Optional[str] = None,
rename: Optional[Dict[str, str]] = None,
) -> "Table":
"""
Extract specified columns into a separate table.
See :ref:`python_api_extract` for details.
:param columns: Single column or list of columns that should be extracted
:param table: Name of table in which the new records should be created
:param fk_column: Name of the foreign key column to populate in the original table
:param rename: Dictionary of columns that should be renamed when populating the new table
"""
rename = rename or {}
if isinstance(columns, str):
columns = [columns]
if not set(columns).issubset(self.columns_dict.keys()):
raise InvalidColumns(
"Invalid columns {} for table with columns {}".format(
columns, list(self.columns_dict.keys())
)
)
with self.db.atomic():
table = table or "_".join(columns)
lookup_table = self.db.table(table)
fk_column = fk_column or "{}_id".format(table)
magic_lookup_column = "{}_{}".format(fk_column, os.urandom(6).hex())
# Populate the lookup table with all of the extracted unique values
lookup_columns_definition = {
(rename.get(col) or col): typ
for col, typ in self.columns_dict.items()
if col in columns
}
if lookup_table.exists():
if not set(lookup_columns_definition.items()).issubset(
lookup_table.columns_dict.items()
):
raise InvalidColumns(
"Lookup table {} already exists but does not have columns {}".format(
table, lookup_columns_definition
)
)
else:
lookup_table.create(
{
**{
"id": int,
},
**lookup_columns_definition,
},
pk="id",
)
lookup_columns = [(rename.get(col) or col) for col in columns]
lookup_table.create_index(lookup_columns, unique=True, if_not_exists=True)
self.db.execute(
"INSERT OR IGNORE INTO {} ({lookup_columns}) SELECT DISTINCT {table_cols} FROM {}".format(
quote_identifier(table),
quote_identifier(self.name),
lookup_columns=", ".join(
quote_identifier(c) for c in lookup_columns
),
table_cols=", ".join(quote_identifier(c) for c in columns),
)
)
# Now add the new fk_column
self.add_column(magic_lookup_column, int)
# And populate it
self.db.execute(
"UPDATE {} SET {} = (SELECT id FROM {} WHERE {where})".format(
quote_identifier(self.name),
quote_identifier(magic_lookup_column),
quote_identifier(table),
where=" AND ".join(
"{}.{} IS {}.{}".format(
quote_identifier(self.name),
quote_identifier(column),
quote_identifier(table),
quote_identifier(rename.get(column) or column),
)
for column in columns
),
)
)
# Figure out the right column order
column_order = []
for c in self.columns:
if c.name in columns and magic_lookup_column not in column_order:
column_order.append(magic_lookup_column)
elif c.name == magic_lookup_column:
continue
else:
column_order.append(c.name)
# Drop the unnecessary columns and rename lookup column
self.transform(
drop=set(columns),
rename={magic_lookup_column: fk_column},
column_order=column_order,
)
# And add the foreign key constraint
self.add_foreign_key(fk_column, table, "id")
return self
def create_index(
self,
columns: Iterable[Union[str, DescIndex]],
index_name: Optional[str] = None,
unique: bool = False,
if_not_exists: bool = False,
find_unique_name: bool = False,
analyze: bool = False,
):
"""
Create an index on this table.
:param columns: A single columns or list of columns to index. These can be strings or,
to create an index using the column in descending order, ``db.DescIndex(column_name)`` objects.
:param index_name: The name to use for the new index. Defaults to the column names joined on ``_``.
:param unique: Should the index be marked as unique, forcing unique values?
:param if_not_exists: Only create the index if one with that name does not already exist.
:param find_unique_name: If ``index_name`` is not provided and the automatically derived name
already exists, keep incrementing a suffix number to find an available name.
:param analyze: Run ``ANALYZE`` against this index after creating it.
See :ref:`python_api_create_index`.
"""
if index_name is None:
index_name = "idx_{}_{}".format(
self.name.replace(" ", "_"), "_".join(columns)
)
columns_sql = []
for column in columns:
if isinstance(column, DescIndex):
columns_sql.append("{} desc".format(quote_identifier(column)))
else:
columns_sql.append(quote_identifier(column))
suffix = None
created_index_name = None
while True:
created_index_name = (
"{}_{}".format(index_name, suffix) if suffix else index_name
)
sql = (
textwrap.dedent("""
CREATE {unique}INDEX {if_not_exists}{index_name}
ON {table_name} ({columns});
""")
.strip()
.format(
index_name=quote_identifier(created_index_name),
table_name=quote_identifier(self.name),
columns=", ".join(columns_sql),
unique="UNIQUE " if unique else "",
if_not_exists="IF NOT EXISTS " if if_not_exists else "",
)
)
try:
self.db.execute(sql)
break
except OperationalError as e:
# find_unique_name=True - try again if 'index ... already exists'
arg = e.args[0]
if (
find_unique_name
and arg.startswith("index ")
and arg.endswith(" already exists")
):
if suffix is None:
suffix = 2
else:
suffix += 1
continue
else:
raise e
if analyze:
self.db.analyze(created_index_name)
return self
def add_column(
self,
col_name: str,
col_type: Optional[Any] = None,
fk: Optional[str] = None,
fk_col: Optional[str] = None,
not_null_default: Optional[Any] = None,
):
"""
Add a column to this table. See :ref:`python_api_add_column`.
:param col_name: Name of the new column
:param col_type: Column type - a Python type such as ``str`` or a SQLite type string such as ``"BLOB"``
:param fk: Name of a table that this column should be a foreign key reference to
:param fk_col: Column in the foreign key table that this should reference
:param not_null_default: Set this column to ``not null`` and give it this default value
"""
fk_col_type = None
if fk is not None:
# fk must be a valid table
if fk not in self.db.table_names():
raise AlterError("table '{}' does not exist".format(fk))
# if fk_col specified, must be a valid column
if fk_col is not None:
if fk_col not in self.db[fk].columns_dict:
raise AlterError("table '{}' has no column {}".format(fk, fk_col))
else:
# automatically set fk_col to first primary_key of fk table
pks = [c for c in self.db[fk].columns if c.is_pk]
if pks:
fk_col = pks[0].name
fk_col_type = pks[0].type
else:
fk_col = "rowid"
fk_col_type = "INTEGER"
if col_type is None:
col_type = str
not_null_sql = None
if not_null_default is not None:
not_null_sql = "NOT NULL DEFAULT {}".format(
self.db.quote_default_value(not_null_default)
)
sql = "ALTER TABLE {} ADD COLUMN {} {col_type}{not_null_default};".format(
quote_identifier(self.name),
quote_identifier(col_name),
col_type=fk_col_type or COLUMN_TYPE_MAPPING[col_type],
not_null_default=(" " + not_null_sql) if not_null_sql else "",
)
self.db.execute(sql)
if fk is not None:
self.add_foreign_key(col_name, fk, fk_col)
return self
def drop(self, ignore: bool = False) -> None:
"""
Drop this table.
:param ignore: Set to ``True`` to ignore the error if the table does not exist
"""
try:
self.db.execute("DROP TABLE {}".format(quote_identifier(self.name)))
except sqlite3.OperationalError:
if not ignore:
raise
def guess_foreign_table(self, column: str) -> str:
"""
For a given column, suggest another table that might be referenced by this
column should it be used as a foreign key.
For example, a column called ``tag_id`` or ``tag`` or ``tags`` might suggest
a ``tag`` table, if one exists.
If no candidates can be found, raises a ``NoObviousTable`` exception.
:param column: Name of column
"""
column = column.lower()
possibilities = [column]
if column.endswith("_id"):
column_without_id = column[:-3]
possibilities.append(column_without_id)
if not column_without_id.endswith("s"):
possibilities.append(column_without_id + "s")
elif not column.endswith("s"):
possibilities.append(column + "s")
existing_tables = {t.lower(): t for t in self.db.table_names()}
for table in possibilities:
if table in existing_tables:
return existing_tables[table]
# If we get here there's no obvious candidate - raise an error
raise NoObviousTable(
"No obvious foreign key table for column '{}' - tried {}".format(
column, repr(possibilities)
)
)
def guess_foreign_column(self, other_table: str) -> str:
pks = [c for c in self.db[other_table].columns if c.is_pk]
if len(pks) != 1:
raise BadPrimaryKey(
"Could not detect single primary key for table '{}'".format(other_table)
)
else:
return pks[0].name
def add_foreign_key(
self,
column: ForeignKeyColumns,
other_table: Optional[str] = None,
other_column: Optional[ForeignKeyColumns] = None,
ignore: bool = False,
on_delete: str = "NO ACTION",
on_update: str = "NO ACTION",
):
"""
Alter the schema to mark the specified column as a foreign key to another table.
:param column: The column to mark as a foreign key - use a tuple of columns
for a compound foreign key.
:param other_table: The table it refers to - if omitted, will be guessed based on the column name.
:param other_column: The column on the other table it - if omitted, will be guessed.
Use a tuple of columns for a compound foreign key.
:param ignore: Set this to ``True`` to ignore an existing foreign key - otherwise a ``AlterError`` will be raised.
:param on_delete: ``ON DELETE`` action for the foreign key, e.g. ``"CASCADE"``
or ``"SET NULL"``.
:param on_update: ``ON UPDATE`` action for the foreign key.
"""
columns = (column,) if isinstance(column, str) else tuple(column)
# Ensure columns exist
for col in columns:
if col not in self.columns_dict:
raise AlterError("No such column: {}".format(col))
# If other_table is not specified, attempt to guess it from the column
if other_table is None:
if len(columns) > 1:
raise ValueError(
"other_table must be specified for a compound foreign key"
)
other_table = self.guess_foreign_table(columns[0])
# If other_column is not specified, detect the primary key on other_table
if other_column is None:
if len(columns) > 1:
other_columns = tuple(self.db.table(other_table).pks)
else:
other_columns = (self.guess_foreign_column(other_table),)
elif isinstance(other_column, str):
other_columns = (other_column,)
else:
other_columns = tuple(other_column)
if len(columns) != len(other_columns):
raise ValueError(
"Compound foreign key must have the same number of columns "
"on both sides"
)
# Soundness check that the other columns exist
for other_col in other_columns:
if (
not [c for c in self.db[other_table].columns if c.name == other_col]
and other_col != "rowid"
):
raise AlterError("No such column: {}.{}".format(other_table, other_col))
# Check we do not already have an existing foreign key
if any(
fk
for fk in self.foreign_keys
if fk.columns == columns
and fk.other_table == other_table
and fk.other_columns == other_columns
):
if ignore:
return self
else:
raise AlterError(
"Foreign key already exists for {} => {}.{}".format(
", ".join(columns), other_table, ", ".join(other_columns)
)
)
if len(columns) == 1:
fk_object = ForeignKey(
self.name,
columns[0],
other_table,
other_columns[0],
on_delete=on_delete,
on_update=on_update,
)
else:
fk_object = ForeignKey(
self.name,
None,
other_table,
None,
columns=columns,
other_columns=other_columns,
is_compound=True,
on_delete=on_delete,
on_update=on_update,
)
self.db.add_foreign_keys([fk_object])
return self
def enable_counts(self) -> None:
"""
Set up triggers to update a cache of the count of rows in this table.
See :ref:`python_api_cached_table_counts` for details.
"""
sql = (
textwrap.dedent("""
{create_counts_table}
CREATE TRIGGER IF NOT EXISTS {trigger_insert} AFTER INSERT ON {table}
BEGIN
INSERT OR REPLACE INTO {counts_table}
VALUES (
{table_quoted},
COALESCE(
(SELECT count FROM {counts_table} WHERE "table" = {table_quoted}),
0
) + 1
);
END;
CREATE TRIGGER IF NOT EXISTS {trigger_delete} AFTER DELETE ON {table}
BEGIN
INSERT OR REPLACE INTO {counts_table}
VALUES (
{table_quoted},
COALESCE(
(SELECT count FROM {counts_table} WHERE "table" = {table_quoted}),
0
) - 1
);
END;
INSERT OR REPLACE INTO _counts VALUES ({table_quoted}, (select count(*) from {table}));
""")
.strip()
.format(
create_counts_table=_COUNTS_TABLE_CREATE_SQL.format(
self.db._counts_table_name
),
counts_table=quote_identifier(self.db._counts_table_name),
table=quote_identifier(self.name),
table_quoted=self.db.quote(self.name),
trigger_insert=quote_identifier(
self.name + self.db._counts_table_name + "_insert"
),
trigger_delete=quote_identifier(
self.name + self.db._counts_table_name + "_delete"
),
)
)
with self.db.atomic():
self.db._executescript(sql)
self.db.use_counts_table = True
@property
def has_counts_triggers(self) -> bool:
"Does this table have triggers setup to update cached counts?"
trigger_names = {
"{table}{counts_table}_{suffix}".format(
counts_table=self.db._counts_table_name, table=self.name, suffix=suffix
)
for suffix in ["insert", "delete"]
}
return trigger_names.issubset(self.triggers_dict.keys())
def enable_fts(
self,
columns: Iterable[str],
fts_version: str = "FTS5",
create_triggers: bool = False,
tokenize: Optional[str] = None,
replace: bool = False,
):
"""
Enable SQLite full-text search against the specified columns.
See :ref:`python_api_fts` for more details.
:param columns: List of column names to include in the search index.
:param fts_version: FTS version to use - defaults to ``FTS5`` but you may want ``FTS4`` for older SQLite versions.
:param create_triggers: Should triggers be created to keep the search index up-to-date? Defaults to ``False``.
:param tokenize: Custom SQLite tokenizer to use, for example ``"porter"`` to enable Porter stemming.
:param replace: Should any existing FTS index for this table be replaced by the new one?
"""
create_fts_sql = (
textwrap.dedent("""
CREATE VIRTUAL TABLE {table_fts} USING {fts_version} (
{columns},{tokenize}
content={table}
)
""")
.strip()
.format(
table=quote_identifier(self.name),
table_fts=quote_identifier(self.name + "_fts"),
columns=", ".join(quote_identifier(c) for c in columns),
fts_version=fts_version,
tokenize="\n tokenize='{}',".format(tokenize) if tokenize else "",
)
)
should_recreate = False
if replace and self.db["{}_fts".format(self.name)].exists():
# Does the table need to be recreated?
fts_schema = self.db["{}_fts".format(self.name)].schema
if fts_schema != create_fts_sql:
should_recreate = True
expected_triggers = {self.name + suffix for suffix in ("_ai", "_ad", "_au")}
existing_triggers = {t.name for t in self.triggers}
has_triggers = existing_triggers.issuperset(expected_triggers)
if has_triggers != create_triggers:
should_recreate = True
if not should_recreate:
# Table with correct configuration already exists
return self
if should_recreate:
self.disable_fts()
self.db.executescript(create_fts_sql)
self.populate_fts(columns)
if create_triggers:
old_cols = ", ".join("old.{}".format(quote_identifier(c)) for c in columns)
new_cols = ", ".join("new.{}".format(quote_identifier(c)) for c in columns)
columns_quoted = ", ".join(quote_identifier(c) for c in columns)
table = quote_identifier(self.name)
table_fts = quote_identifier(self.name + "_fts")
triggers = (
textwrap.dedent("""
CREATE TRIGGER {table_ai} AFTER INSERT ON {table} BEGIN
INSERT INTO {table_fts} (rowid, {columns}) VALUES (new.rowid, {new_cols});
END;
CREATE TRIGGER {table_ad} AFTER DELETE ON {table} BEGIN
INSERT INTO {table_fts} ({table_fts}, rowid, {columns}) VALUES('delete', old.rowid, {old_cols});
END;
CREATE TRIGGER {table_au} AFTER UPDATE ON {table} BEGIN
INSERT INTO {table_fts} ({table_fts}, rowid, {columns}) VALUES('delete', old.rowid, {old_cols});
INSERT INTO {table_fts} (rowid, {columns}) VALUES (new.rowid, {new_cols});
END;
""")
.strip()
.format(
table=table,
table_fts=table_fts,
table_ai=quote_identifier(self.name + "_ai"),
table_ad=quote_identifier(self.name + "_ad"),
table_au=quote_identifier(self.name + "_au"),
columns=columns_quoted,
old_cols=old_cols,
new_cols=new_cols,
)
)
self.db.executescript(triggers)
return self
def populate_fts(self, columns: Iterable[str]) -> "Table":
"""
Update the associated SQLite full-text search index with the latest data from the
table for the specified columns.
:param columns: Columns to populate the data for
"""
columns_quoted = ", ".join(quote_identifier(c) for c in columns)
sql = (
textwrap.dedent("""
INSERT INTO {table_fts} (rowid, {columns})
SELECT rowid, {columns} FROM {table};
""")
.strip()
.format(
table=quote_identifier(self.name),
table_fts=quote_identifier(self.name + "_fts"),
columns=columns_quoted,
)
)
self.db.executescript(sql)
return self
def disable_fts(self) -> "Table":
"Remove any full-text search index and related triggers configured for this table."
fts_table = self.detect_fts()
if fts_table:
self.db[fts_table].drop()
# Now delete the triggers that related to that table
sql = textwrap.dedent("""
SELECT name FROM sqlite_master
WHERE type = 'trigger'
AND (sql LIKE '% INSERT INTO [{}]%' OR sql LIKE '% INSERT INTO "{}"%')
""").strip().format(fts_table, fts_table)
trigger_names = []
for row in self.db.execute(sql).fetchall():
trigger_names.append(row[0])
with self.db.atomic():
for trigger_name in trigger_names:
self.db.execute(
"DROP TRIGGER IF EXISTS {}".format(quote_identifier(trigger_name))
)
return self
def rebuild_fts(self) -> "Table":
"Run the ``rebuild`` operation against the associated full-text search index table."
fts_table = self.detect_fts()
if fts_table is None:
# Assume this is itself an FTS table
fts_table = self.name
with self.db.atomic():
self.db.execute(
"INSERT INTO {table}({table}) VALUES('rebuild');".format(
table=quote_identifier(fts_table)
)
)
return self
def detect_fts(self) -> Optional[str]:
"Detect if table has a corresponding FTS virtual table and return it"
sql = textwrap.dedent("""
SELECT name FROM sqlite_master
WHERE rootpage = 0
AND (
sql LIKE :like
OR sql LIKE :like2
OR (
tbl_name = :table
AND sql LIKE '%VIRTUAL TABLE%USING FTS%'
)
)
""").strip()
args = {
"like": "%VIRTUAL TABLE%USING FTS%content=[{}]%".format(self.name),
"like2": '%VIRTUAL TABLE%USING FTS%content="{}"%'.format(self.name),
"table": self.name,
}
rows = self.db.execute(sql, args).fetchall()
if len(rows) == 0:
return None
else:
return rows[0][0]
def optimize(self) -> "Table":
"Run the ``optimize`` operation against the associated full-text search index table."
fts_table = self.detect_fts()
if fts_table is not None:
with self.db.atomic():
self.db.execute("""
INSERT INTO {table} ({table}) VALUES ("optimize");
""".strip().format(table=quote_identifier(fts_table)))
return self
def search_sql(
self,
columns: Optional[Iterable[str]] = None,
order_by: Optional[str] = None,
limit: Optional[int] = None,
offset: Optional[int] = None,
where: Optional[str] = None,
include_rank: bool = False,
) -> str:
""" "
Return SQL string that can be used to execute searches against this table.
:param columns: Columns to search against
:param order_by: Column or SQL expression to sort by
:param limit: SQL limit
:param offset: SQL offset
:param where: Extra SQL fragment for the WHERE clause
:param include_rank: Select the search rank column in the final query
"""
# Pick names for table and rank column that don't clash
original = "original_" if self.name == "original" else "original"
original_quoted = quote_identifier(original)
columns_sql = "*"
columns_with_prefix_sql = "{}.*".format(original_quoted)
if columns:
columns_sql = ",\n ".join(quote_identifier(c) for c in columns)
columns_with_prefix_sql = ",\n ".join(
"{}.{}".format(original_quoted, quote_identifier(c)) for c in columns
)
fts_table = self.detect_fts()
if not fts_table:
raise ValueError(
"Full-text search is not configured for table '{}'".format(self.name)
)
fts_table_quoted = quote_identifier(fts_table)
virtual_table_using = self.db.table(fts_table).virtual_table_using
sql = textwrap.dedent("""
with {original} as (
select
rowid,
{columns}
from {dbtable}{where_clause}
)
select
{columns_with_prefix}
from
{original}
join {fts_table} on {original}.rowid = {fts_table}.rowid
where
{fts_table} match :query
order by
{order_by}
{limit_offset}
""").strip()
if virtual_table_using == "FTS5":
rank_implementation = "{}.rank".format(fts_table_quoted)
else:
self.db.register_fts4_bm25()
rank_implementation = "rank_bm25(matchinfo({}, 'pcnalx'))".format(
fts_table_quoted
)
if include_rank:
columns_with_prefix_sql += ",\n " + rank_implementation + " rank"
limit_offset = ""
if limit is not None:
limit_offset += " limit {}".format(limit)
if offset is not None:
limit_offset += " offset {}".format(offset)
return sql.format(
dbtable=quote_identifier(self.name),
where_clause="\n where {}".format(where) if where else "",
original=original_quoted,
columns=columns_sql,
columns_with_prefix=columns_with_prefix_sql,
fts_table=fts_table_quoted,
order_by=order_by or rank_implementation,
limit_offset=limit_offset.strip(),
).strip()
def search(
self,
q: str,
order_by: Optional[str] = None,
columns: Optional[Iterable[str]] = None,
limit: Optional[int] = None,
offset: Optional[int] = None,
where: Optional[str] = None,
where_args: Optional[Union[Iterable, dict]] = None,
include_rank: bool = False,
quote: bool = False,
) -> Generator[dict, None, None]:
"""
Execute a search against this table using SQLite full-text search, returning a sequence of
dictionaries for each row.
:param q: Terms to search for
:param order_by: Defaults to order by rank, or specify a column here.
:param columns: List of columns to return, defaults to all columns.
:param limit: Optional integer limit for returned rows.
:param offset: Optional integer SQL offset.
:param where: Extra SQL fragment for the WHERE clause
:param where_args: Arguments to use for :param placeholders in the extra WHERE clause
:param include_rank: Select the search rank column in the final query
:param quote: Apply quoting to disable any special characters in the search query
See :ref:`python_api_fts_search`.
"""
args = {"query": self.db.quote_fts(q) if quote else q}
if where_args and "query" in where_args:
raise ValueError(
"'query' is a reserved key and cannot be passed to where_args for .search()"
)
if where_args:
args.update(where_args)
cursor = self.db.execute(
self.search_sql(
order_by=order_by,
columns=columns,
limit=limit,
offset=offset,
where=where,
include_rank=include_rank,
),
args,
)
columns = [c[0] for c in cursor.description]
for row in cursor:
yield dict(zip(columns, row))
def value_or_default(self, key: str, value: Any) -> Any:
return self._defaults[key] if value is DEFAULT else value
def delete(self, pk_values: Union[list, tuple, str, int, float]) -> "Table":
"""
Delete row matching the specified primary key.
:param pk_values: A single value, or a tuple of values for tables that have a compound primary key
"""
if not isinstance(pk_values, (list, tuple)):
pk_values = [pk_values]
self.get(pk_values)
wheres = ["{} = ?".format(quote_identifier(pk_name)) for pk_name in self.pks]
sql = "delete from {} where {wheres}".format(
quote_identifier(self.name), wheres=" and ".join(wheres)
)
with self.db.atomic():
self.db.execute(sql, pk_values)
return self
def delete_where(
self,
where: Optional[str] = None,
where_args: Optional[Union[Sequence, Dict[str, Any]]] = None,
analyze: bool = False,
) -> "Table":
"""
Delete rows matching the specified where clause, or delete all rows in the table.
See :ref:`python_api_delete_where`.
:param where: SQL where fragment to use, for example ``id > ?``
:param where_args: Parameters to use with that fragment - an iterable for ``id > ?``
parameters, or a dictionary for ``id > :id``
:param analyze: Set to ``True`` to run ``ANALYZE`` after the rows have been deleted.
"""
if not self.exists():
return self
sql = "delete from {}".format(quote_identifier(self.name))
if where is not None:
sql += " where " + where
with self.db.atomic():
self.db.execute(sql, where_args or [])
if analyze:
self.analyze()
return self
def update(
self,
pk_values: Union[list, tuple, str, int, float],
updates: Optional[dict] = None,
alter: bool = False,
conversions: Optional[dict] = None,
) -> "Table":
"""
Execute a SQL ``UPDATE`` against the specified row.
See :ref:`python_api_update`.
:param pk_values: The primary key of an individual record - can be a tuple if the
table has a compound primary key.
:param updates: A dictionary mapping columns to their updated values.
:param alter: Set to ``True`` to add any missing columns.
:param conversions: Optional dictionary of SQL functions to apply during the update, for example
``{"mycolumn": "upper(?)"}``.
"""
updates = updates or {}
conversions = conversions or {}
if not isinstance(pk_values, (list, tuple)):
pk_values = [pk_values]
# Soundness check that the record exists (raises error if not):
self.get(pk_values)
if not updates:
return self
args = []
sets = []
wheres = []
pks = self.pks
for key, value in updates.items():
sets.append(
"{} = {}".format(quote_identifier(key), conversions.get(key, "?"))
)
args.append(jsonify_if_needed(value))
wheres = ["{} = ?".format(quote_identifier(pk_name)) for pk_name in pks]
args.extend(pk_values)
sql = "update {} set {sets} where {wheres}".format(
quote_identifier(self.name),
sets=", ".join(sets),
wheres=" and ".join(wheres),
)
with self.db.atomic():
try:
rowcount = self.db.execute(sql, args).rowcount
except OperationalError as e:
if alter and (" column" in e.args[0]):
# Attempt to add any missing columns, then try again
self.add_missing_columns([updates])
rowcount = self.db.execute(sql, args).rowcount
else:
raise
# TODO: Test this works (rolls back) - use better exception:
assert rowcount == 1
self.last_pk = pk_values[0] if len(pks) == 1 else pk_values
return self
def convert(
self,
columns: Union[str, List[str]],
fn: Callable,
output: Optional[str] = None,
output_type: Optional[Any] = None,
drop: bool = False,
multi: bool = False,
where: Optional[str] = None,
where_args: Optional[Union[Sequence, Dict[str, Any]]] = None,
show_progress: bool = False,
) -> "Table":
"""
Apply conversion function ``fn`` to every value in the specified columns.
:param columns: A single column or list of string column names to convert.
:param fn: A callable that takes a single argument, ``value``, and returns it converted.
:param output: Optional string column name to write the results to (defaults to the input column).
:param output_type: If the output column needs to be created, this is the type that will be used
for the new column.
:param drop: Should the original column be dropped once the conversion is complete?
:param multi: If ``True`` the return value of ``fn(value)`` will be expected to be a
dictionary, and new columns will be created for each key of that dictionary.
:param where: SQL fragment to use as a ``WHERE`` clause to limit the rows to which the conversion
is applied, for example ``age > ?`` or ``age > :age``.
:param where_args: List of arguments (if using ``?``) or a dictionary (if using ``:age``).
:param show_progress: Should a progress bar be displayed?
See :ref:`python_api_convert`.
"""
if isinstance(columns, str):
columns = [columns]
if multi:
return self._convert_multi(
columns[0],
fn,
drop=drop,
where=where,
where_args=where_args,
show_progress=show_progress,
)
if output is not None:
if len(columns) != 1:
raise ValueError("output= can only be used with a single column")
if output not in self.columns_dict:
self.add_column(output, output_type or "text")
todo_count = self.count_where(where, where_args) * len(columns)
with progressbar(length=todo_count, silent=not show_progress) as bar:
def convert_value(v):
bar.update(1)
return jsonify_if_needed(fn(v))
fn_name = getattr(fn, "__name__", "fn")
if fn_name == "<lambda>":
fn_name = f"lambda_{abs(hash(fn))}"
self.db.register_function(convert_value, name=fn_name)
sql = "update {} set {sets}{where};".format(
quote_identifier(self.name),
sets=", ".join(
[
"{} = {}({})".format(
quote_identifier(output or column),
fn_name,
quote_identifier(column),
)
for column in columns
]
),
where=" where {}".format(where) if where is not None else "",
)
with self.db.atomic():
self.db.execute(sql, where_args or [])
if drop:
self.transform(drop=columns)
return self
def _convert_multi(
self, column, fn, drop, show_progress, where=None, where_args=None
):
# First we execute the function
pk_to_values = {}
new_column_types: Dict[str, Set[type]] = {}
pks = [column.name for column in self.columns if column.is_pk]
if not pks:
pks = ["rowid"]
with progressbar(
length=self.count, silent=not show_progress, label="1: Evaluating"
) as bar:
for row in self.rows_where(
select=", ".join(
quote_identifier(column_name) for column_name in (pks + [column])
),
where=where,
where_args=where_args,
):
row_pk = tuple(row[pk] for pk in pks)
if len(row_pk) == 1:
row_pk = row_pk[0]
values = fn(row[column])
if values is not None and not isinstance(values, dict):
raise BadMultiValues(values)
if values:
for key, value in values.items():
new_column_types.setdefault(key, set()).add(type(value))
pk_to_values[row_pk] = values
bar.update(1)
# Add any new columns
columns_to_create = types_for_column_types(new_column_types)
for column_name, column_type in columns_to_create.items():
if column_name not in self.columns_dict:
self.add_column(column_name, column_type)
# Run the updates
with progressbar(
length=self.count, silent=not show_progress, label="2: Updating"
) as bar:
with self.db.atomic():
for pk, updates in pk_to_values.items():
self.update(pk, updates)
bar.update(1)
if drop:
self.transform(drop=(column,))
def build_insert_queries_and_params(
self,
extracts,
chunk,
all_columns,
hash_id,
hash_id_columns,
upsert,
pk,
not_null,
conversions,
num_records_processed,
replace,
ignore,
list_mode=False,
):
"""
Given a list ``chunk`` of records that should be written to *this* table,
return a list of ``(sql, parameters)`` 2-tuples which, when executed in
order, perform the desired INSERT / UPSERT / REPLACE operation.
"""
# Dict-mode insert({}) has no explicit columns; SQLite spells that as
# DEFAULT VALUES. List mode with no columns is a different input shape.
if not list_mode and not all_columns:
if upsert:
raise PrimaryKeyRequired(
"upsert() requires a value for the primary key - "
"an empty record cannot be upserted"
)
or_clause = ""
if replace:
or_clause = " OR REPLACE"
elif ignore:
or_clause = " OR IGNORE"
sql = (
f"INSERT{or_clause} INTO {quote_identifier(self.name)} "
"DEFAULT VALUES"
)
return [(sql, []) for _ in chunk]
if hash_id_columns and hash_id is None:
hash_id = "id"
extracts = resolve_extracts(extracts)
# Build a row-list ready for executemany-style flattening
values = []
if list_mode:
# In list mode, records are already lists of values
num_columns = len(all_columns)
has_extracts = bool(extracts)
for record in chunk:
# Pad short records with None, truncate long ones
record_len = len(record)
if record_len < num_columns:
record_values = [jsonify_if_needed(v) for v in record] + [None] * (
num_columns - record_len
)
else:
record_values = [jsonify_if_needed(v) for v in record[:num_columns]]
# Only process extracts if there are any
if has_extracts:
for i, key in enumerate(all_columns):
if key in extracts:
record_values[i] = self.db.table(extracts[key]).lookup(
{"value": record_values[i]}
)
values.append(record_values)
else:
# Dict mode: original logic
for record in chunk:
record_values = []
for key in all_columns:
value = jsonify_if_needed(
record.get(
key,
(
None
if key != hash_id
else hash_record(record, hash_id_columns)
),
)
)
if key in extracts:
extract_table = extracts[key]
value = self.db.table(extract_table).lookup({"value": value})
record_values.append(value)
values.append(record_values)
columns_sql = ", ".join(quote_identifier(c) for c in all_columns)
placeholder_expr = ", ".join(conversions.get(c, "?") for c in all_columns)
row_placeholders_sql = ", ".join(f"({placeholder_expr})" for _ in values)
flat_params = list(itertools.chain.from_iterable(values))
# replace=True mean INSERT OR REPLACE INTO
if replace:
sql = (
f"INSERT OR REPLACE INTO {quote_identifier(self.name)} "
f"({columns_sql}) VALUES {row_placeholders_sql}"
)
return [(sql, flat_params)]
# If not an upsert it's an INSERT, maybe with OR IGNORE
if not upsert:
or_ignore = ""
if ignore:
or_ignore = " OR IGNORE"
sql = (
f"INSERT{or_ignore} INTO {quote_identifier(self.name)} "
f"({columns_sql}) VALUES {row_placeholders_sql}"
)
return [(sql, flat_params)]
# Everything from here on is for upsert=True
pk_cols = [pk] if isinstance(pk, str) else list(pk)
# Every record must provide a value for every primary key column - a
# NULL primary key never matches ON CONFLICT, so the record would be
# inserted as a brand new row instead of upserted
missing_pk_cols = [c for c in pk_cols if c not in all_columns]
if missing_pk_cols:
raise PrimaryKeyRequired(
"upsert() requires a value for the primary key column{}: {}".format(
"s" if len(missing_pk_cols) > 1 else "",
", ".join(missing_pk_cols),
)
)
pk_indexes = [all_columns.index(c) for c in pk_cols]
for record_values in values:
if any(record_values[i] is None for i in pk_indexes):
raise PrimaryKeyRequired(
"upsert() requires a value for the primary key column{}: {}".format(
"s" if len(pk_cols) > 1 else "",
", ".join(pk_cols),
)
)
non_pk_cols = [c for c in all_columns if c not in pk_cols]
conflict_sql = ", ".join(quote_identifier(c) for c in pk_cols)
if self.db.supports_on_conflict and not self.db.use_old_upsert:
if non_pk_cols:
# DO UPDATE
assignments = []
for c in non_pk_cols:
c_quoted = quote_identifier(c)
if c in conversions:
assignments.append(
f"{c_quoted} = {conversions[c].replace('?', f'excluded.{c_quoted}')}"
)
else:
assignments.append(f"{c_quoted} = excluded.{c_quoted}")
do_clause = "DO UPDATE SET " + ", ".join(assignments)
else:
# All columns are in the PK – nothing to update.
do_clause = "DO NOTHING"
sql = (
f"INSERT INTO {quote_identifier(self.name)} ({columns_sql}) "
f"VALUES {row_placeholders_sql} "
f"ON CONFLICT({conflict_sql}) {do_clause}"
)
return [(sql, flat_params)]
# At this point we need compatibility UPSERT for SQLite < 3.24.0
# (INSERT OR IGNORE + second UPDATE stage)
queries_and_params = []
if isinstance(pk, str):
pks = [pk]
else:
pks = pk
self.last_pk = None
for record_values in values:
record = dict(zip(all_columns, record_values))
placeholders = list(pks)
# Need to populate not-null columns too, or INSERT OR IGNORE ignores
# them since it ignores the resulting integrity errors
if not_null:
placeholders.extend(not_null)
sql = (
"INSERT OR IGNORE INTO {table}({cols}) VALUES({placeholders});".format(
table=quote_identifier(self.name),
cols=", ".join([quote_identifier(p) for p in placeholders]),
placeholders=", ".join(["?" for p in placeholders]),
)
)
queries_and_params.append(
(sql, [record[col] for col in pks] + ["" for _ in (not_null or [])])
)
# UPDATE "book" SET "name" = 'Programming' WHERE "id" = 1001;
set_cols = [col for col in all_columns if col not in pks]
if set_cols:
sql2 = "UPDATE {} SET {pairs} WHERE {wheres}".format(
quote_identifier(self.name),
pairs=", ".join(
"{} = {}".format(
quote_identifier(col), conversions.get(col, "?")
)
for col in set_cols
),
wheres=" AND ".join(
"{} = ?".format(quote_identifier(pk)) for pk in pks
),
)
queries_and_params.append(
(
sql2,
[record[col] for col in set_cols] + [record[pk] for pk in pks],
)
)
# We can populate .last_pk right here
if num_records_processed == 1:
pk_values = tuple(record[pk] for pk in pks)
if len(pk_values) == 1:
self.last_pk = pk_values[0]
else:
self.last_pk = pk_values
return queries_and_params
def insert_chunk(
self,
alter,
extracts,
chunk,
all_columns,
hash_id,
hash_id_columns,
upsert,
pk,
not_null,
conversions,
num_records_processed,
replace,
ignore,
list_mode=False,
) -> Optional[sqlite3.Cursor]:
queries_and_params = self.build_insert_queries_and_params(
extracts,
chunk,
all_columns,
hash_id,
hash_id_columns,
upsert,
pk,
not_null,
conversions,
num_records_processed,
replace,
ignore,
list_mode,
)
result = None
with self.db.atomic():
for query, params in queries_and_params:
try:
result = self.db.execute(query, params)
except OperationalError as e:
if alter and (" column" in e.args[0]):
# Attempt to add any missing columns, then try again
self.add_missing_columns(chunk)
result = self.db.execute(query, params)
elif e.args[0] == "too many SQL variables":
first_half = chunk[: len(chunk) // 2]
second_half = chunk[len(chunk) // 2 :]
self.insert_chunk(
alter,
extracts,
first_half,
all_columns,
hash_id,
hash_id_columns,
upsert,
pk,
not_null,
conversions,
num_records_processed,
replace,
ignore,
list_mode,
)
result = self.insert_chunk(
alter,
extracts,
second_half,
all_columns,
hash_id,
hash_id_columns,
upsert,
pk,
not_null,
conversions,
num_records_processed,
replace,
ignore,
list_mode,
)
else:
raise
return result
def insert(
self,
record: Dict[str, Any],
pk=DEFAULT,
foreign_keys=DEFAULT,
column_order: Optional[Union[List[str], Default]] = DEFAULT,
not_null: Optional[Union[Iterable[str], Default]] = DEFAULT,
defaults: Optional[Union[Dict[str, Any], Default]] = DEFAULT,
hash_id: Optional[Union[str, Default]] = DEFAULT,
hash_id_columns: Optional[Union[Iterable[str], Default]] = DEFAULT,
alter: Optional[Union[bool, Default]] = DEFAULT,
ignore: Optional[Union[bool, Default]] = DEFAULT,
replace: Optional[Union[bool, Default]] = DEFAULT,
extracts: Optional[Union[Dict[str, str], List[str], Default]] = DEFAULT,
conversions: Optional[Union[Dict[str, str], Default]] = DEFAULT,
columns: Optional[Union[Dict[str, Any], Default]] = DEFAULT,
strict: Optional[Union[bool, Default]] = DEFAULT,
) -> "Table":
"""
Insert a single record into the table. The table will be created with a schema that matches
the inserted record if it does not already exist, see :ref:`python_api_creating_tables`.
- ``record`` - required: a dictionary representing the record to be inserted.
The other parameters are optional, and mostly influence how the new table will be created if
that table does not exist yet.
Each of them defaults to ``DEFAULT``, which indicates that the default setting for the current
``Table`` object (specified in the table constructor) should be used.
:param record: Dictionary record to be inserted
:param pk: If creating the table, which column should be the primary key.
:param foreign_keys: See :ref:`python_api_foreign_keys`.
:param column_order: List of strings specifying a full or partial column order
to use when creating the table.
:param not_null: Set of strings specifying columns that should be ``NOT NULL``.
:param defaults: Dictionary specifying default values for specific columns.
:param hash_id: Name of a column to create and use as a primary key, where the
value of that primary key will be derived as a SHA1 hash of the other column values
in the record. ``hash_id="id"`` is a common column name used for this.
:param alter: Boolean, should any missing columns be added automatically?
:param ignore: Boolean, if a record already exists with this primary key, ignore this insert.
:param replace: Boolean, if a record already exists with this primary key, replace it with this new record.
:param extracts: A list of columns to extract to other tables, or a dictionary that maps
``{column_name: other_table_name}``. See :ref:`python_api_extracts`.
:param conversions: Dictionary specifying SQL conversion functions to be applied to the data while it
is being inserted, for example ``{"name": "upper(?)"}``. See :ref:`python_api_conversions`.
:param columns: Dictionary over-riding the detected types used for the columns, for example
``{"age": int, "weight": float}``.
:param strict: Boolean, apply STRICT mode if creating the table.
"""
return self.insert_all(
[record],
pk=pk,
foreign_keys=foreign_keys,
column_order=column_order,
not_null=not_null,
defaults=defaults,
hash_id=hash_id,
hash_id_columns=hash_id_columns,
alter=alter,
ignore=ignore,
replace=replace,
extracts=extracts,
conversions=conversions,
columns=columns,
strict=strict,
)
def insert_all(
self,
records: Union[
Iterable[Dict[str, Any]],
Iterable[Sequence[Any]],
],
pk=DEFAULT,
foreign_keys=DEFAULT,
column_order=DEFAULT,
not_null=DEFAULT,
defaults=DEFAULT,
batch_size=DEFAULT,
hash_id=DEFAULT,
hash_id_columns=DEFAULT,
alter=DEFAULT,
ignore=DEFAULT,
replace=DEFAULT,
truncate=False,
extracts=DEFAULT,
conversions=DEFAULT,
columns=DEFAULT,
upsert=False,
analyze=False,
strict=DEFAULT,
) -> "Table":
"""
Like ``.insert()`` but takes a list of records and ensures that the table
that it creates (if table does not exist) has columns for ALL of that data.
Use ``analyze=True`` to run ``ANALYZE`` after the insert has completed.
"""
pk = self.value_or_default("pk", pk)
foreign_keys = self.value_or_default("foreign_keys", foreign_keys)
column_order = self.value_or_default("column_order", column_order)
not_null = self.value_or_default("not_null", not_null)
defaults = self.value_or_default("defaults", defaults)
batch_size = self.value_or_default("batch_size", batch_size)
hash_id = self.value_or_default("hash_id", hash_id)
hash_id_columns = self.value_or_default("hash_id_columns", hash_id_columns)
alter = self.value_or_default("alter", alter)
ignore = self.value_or_default("ignore", ignore)
replace = self.value_or_default("replace", replace)
extracts = self.value_or_default("extracts", extracts)
conversions = self.value_or_default("conversions", conversions) or {}
columns = self.value_or_default("columns", columns)
strict = self.value_or_default("strict", strict)
if hash_id_columns and hash_id is None:
hash_id = "id"
if upsert and not pk and not hash_id and self.exists():
existing_pks = [column.name for column in self.columns if column.is_pk]
if existing_pks:
pk = existing_pks[0] if len(existing_pks) == 1 else tuple(existing_pks)
if upsert and (not pk and not hash_id):
raise PrimaryKeyRequired("upsert() requires a pk")
if hash_id and pk:
raise ValueError("Use either pk= or hash_id=")
if hash_id_columns and (hash_id is None):
hash_id = "id"
if hash_id:
pk = hash_id
if ignore and replace:
raise ValueError("Use either ignore=True or replace=True, not both")
all_columns = []
first = True
num_records_processed = 0
# Detect if we're using list-based iteration or dict-based iteration
list_mode = False
column_names: List[str] = []
# Fix up any records with square braces in the column names (only for dict mode)
# We'll handle this differently for list mode
records_iter = iter(records)
# Peek at first record to determine mode:
try:
first_record = next(records_iter)
except StopIteration:
return self # It was an empty list
# Check if this is list mode or dict mode
if isinstance(first_record, (list, tuple)):
# List/tuple mode: first record should be column names
list_mode = True
if not all(isinstance(col, str) for col in first_record):
raise ValueError(
"When using list-based iteration, the first yielded value must be a list of column name strings"
)
column_names = cast(List[str], list(first_record))
all_columns = column_names
num_columns = len(column_names)
# Get the actual first data record
try:
first_record = next(records_iter)
except StopIteration:
return self # Only headers, no data
if not isinstance(first_record, (list, tuple)):
raise ValueError(
"After column names list, all subsequent records must also be lists"
)
else:
# Dict mode: traditional behavior
records_iter = itertools.chain([first_record], records_iter)
try:
first_record = next(records_iter)
except StopIteration:
return self
first_record = cast(Dict[str, Any], first_record)
num_columns = len(first_record.keys())
if num_columns > SQLITE_MAX_VARS:
raise ValueError(
"Rows can have a maximum of {} columns".format(SQLITE_MAX_VARS)
)
batch_size = (
1
if num_columns == 0
else max(1, min(batch_size, SQLITE_MAX_VARS // num_columns))
)
self.last_rowid = None
self.last_pk = None
if truncate and self.exists():
with self.db.atomic():
self.db.execute("DELETE FROM {};".format(quote_identifier(self.name)))
result = None
for chunk in chunks(itertools.chain([first_record], records_iter), batch_size):
chunk = list(chunk)
num_records_processed += len(chunk)
if first:
if not self.exists():
# Use the first batch to derive the table names
if list_mode:
# Convert list records to dicts for type detection
chunk_as_dicts = [dict(zip(column_names, row)) for row in chunk]
column_types = suggest_column_types(chunk_as_dicts)
else:
dict_chunk = cast(List[Dict[str, Any]], chunk)
column_types = suggest_column_types(dict_chunk)
if extracts:
for col in extracts:
if col in column_types:
column_types[col] = (
int # This will be an integer foreign key
)
column_types.update(columns or {})
self.create(
column_types,
pk,
foreign_keys,
column_order=column_order,
not_null=not_null,
defaults=defaults,
hash_id=hash_id,
hash_id_columns=hash_id_columns,
extracts=extracts,
strict=strict,
)
if list_mode:
# In list mode, columns are already known
all_columns = list(column_names)
if hash_id:
all_columns.insert(0, hash_id)
else:
all_columns_set: Set[str] = set()
for record in cast(List[Dict[str, Any]], chunk):
all_columns_set.update(record.keys())
all_columns = list(sorted(all_columns_set))
if hash_id:
all_columns.insert(0, hash_id)
else:
if not list_mode:
for record in cast(List[Dict[str, Any]], chunk):
all_columns += [
column for column in record if column not in all_columns
]
first = False
result = self.insert_chunk(
alter,
extracts,
chunk,
all_columns,
hash_id,
hash_id_columns,
upsert,
pk,
not_null,
conversions,
num_records_processed,
replace,
ignore,
list_mode,
)
# If we only handled a single row populate self.last_pk
if num_records_processed == 1:
# For an insert we need to use result.lastrowid
if not upsert and result is not None:
self.last_rowid = result.lastrowid
if (hash_id or pk) and self.last_rowid:
# Set self.last_pk to the pk(s) for that rowid
row = list(self.rows_where("rowid = ?", [self.last_rowid]))[0]
if hash_id:
self.last_pk = row[hash_id]
elif isinstance(pk, str):
self.last_pk = row[pk]
else:
self.last_pk = tuple(row[p] for p in pk)
else:
self.last_pk = self.last_rowid
else:
# For an upsert use first_record from earlier
if list_mode:
# In list mode, look up pk value by column index
first_record_list = cast(Sequence[Any], first_record)
if hash_id:
# hash_id not supported in list mode for last_pk
pass
elif isinstance(pk, str):
pk_index = column_names.index(pk)
self.last_pk = first_record_list[pk_index]
else:
self.last_pk = tuple(
first_record_list[column_names.index(p)] for p in pk
)
else:
first_record_dict = cast(Dict[str, Any], first_record)
if hash_id:
self.last_pk = hash_record(first_record_dict, hash_id_columns)
else:
self.last_pk = (
first_record_dict[pk]
if isinstance(pk, str)
else tuple(first_record_dict[p] for p in pk)
)
if analyze:
self.analyze()
return self
def upsert(
self,
record,
pk=DEFAULT,
foreign_keys=DEFAULT,
column_order=DEFAULT,
not_null=DEFAULT,
defaults=DEFAULT,
hash_id=DEFAULT,
hash_id_columns=DEFAULT,
alter=DEFAULT,
extracts=DEFAULT,
conversions=DEFAULT,
columns=DEFAULT,
strict=DEFAULT,
) -> "Table":
"""
Like ``.insert()`` but performs an ``UPSERT``, where records are inserted if they do
not exist and updated if they DO exist, based on matching against their primary key.
See :ref:`python_api_upsert`.
"""
return self.upsert_all(
[record],
pk=pk,
foreign_keys=foreign_keys,
column_order=column_order,
not_null=not_null,
defaults=defaults,
hash_id=hash_id,
hash_id_columns=hash_id_columns,
alter=alter,
extracts=extracts,
conversions=conversions,
columns=columns,
strict=strict,
)
def upsert_all(
self,
records: Union[
Iterable[Dict[str, Any]],
Iterable[Sequence[Any]],
],
pk=DEFAULT,
foreign_keys=DEFAULT,
column_order=DEFAULT,
not_null=DEFAULT,
defaults=DEFAULT,
batch_size=DEFAULT,
hash_id=DEFAULT,
hash_id_columns=DEFAULT,
alter=DEFAULT,
extracts=DEFAULT,
conversions=DEFAULT,
columns=DEFAULT,
analyze=False,
strict=DEFAULT,
) -> "Table":
"""
Like ``.upsert()`` but can be applied to a list of records.
"""
return self.insert_all(
records,
pk=pk,
foreign_keys=foreign_keys,
column_order=column_order,
not_null=not_null,
defaults=defaults,
batch_size=batch_size,
hash_id=hash_id,
hash_id_columns=hash_id_columns,
alter=alter,
extracts=extracts,
conversions=conversions,
columns=columns,
upsert=True,
analyze=analyze,
strict=strict,
)
def add_missing_columns(self, records: Iterable[Dict[str, Any]]) -> "Table":
needed_columns = suggest_column_types(records)
current_columns = {c.lower() for c in self.columns_dict}
for col_name, col_type in needed_columns.items():
if col_name.lower() not in current_columns:
self.add_column(col_name, col_type)
return self
def lookup(
self,
lookup_values: Dict[str, Any],
extra_values: Optional[Dict[str, Any]] = None,
pk: Optional[str] = "id",
foreign_keys: Optional[ForeignKeysType] = None,
column_order: Optional[List[str]] = None,
not_null: Optional[Iterable[str]] = None,
defaults: Optional[Dict[str, Any]] = None,
extracts: Optional[Union[Dict[str, str], List[str]]] = None,
conversions: Optional[Dict[str, str]] = None,
columns: Optional[Dict[str, Any]] = None,
strict: Optional[bool] = False,
):
"""
Create or populate a lookup table with the specified values.
``db["Species"].lookup({"name": "Palm"})`` will create a table called ``Species``
(if one does not already exist) with two columns: ``id`` and ``name``. It will
set up a unique constraint on the ``name`` column to guarantee it will not
contain duplicate rows.
It will then insert a new row with the ``name`` set to ``Palm`` and return the
new integer primary key value.
An optional second argument can be provided with more ``name: value`` pairs to
be included only if the record is being created for the first time. These will
be ignored on subsequent lookup calls for records that already exist.
All other keyword arguments are passed through to ``.insert()``.
See :ref:`python_api_lookup_tables` for more details.
:param lookup_values: Dictionary specifying column names and values to use for the lookup
:param extra_values: Additional column values to be used only if creating a new record
:param strict: Boolean, apply STRICT mode if creating the table.
"""
if not isinstance(lookup_values, dict):
raise ValueError("lookup_values must be a dictionary")
if pk is None:
raise ValueError("pk cannot be None")
if extra_values is not None and not isinstance(extra_values, dict):
raise ValueError("extra_values must be a dictionary")
combined_values = dict(lookup_values)
if extra_values is not None:
combined_values.update(extra_values)
if self.exists():
self.add_missing_columns([combined_values])
unique_column_sets = [set(i.columns) for i in self.indexes]
if set(lookup_values.keys()) not in unique_column_sets:
self.create_index(lookup_values.keys(), unique=True)
wheres = [
"{} = ?".format(quote_identifier(column)) for column in lookup_values
]
rows = list(
self.rows_where(
" and ".join(wheres), [value for _, value in lookup_values.items()]
)
)
try:
return rows[0][pk]
except IndexError:
return self.insert(
combined_values,
pk=pk,
foreign_keys=foreign_keys,
column_order=column_order,
not_null=not_null,
defaults=defaults,
extracts=extracts,
conversions=conversions,
columns=columns,
strict=strict,
).last_pk
else:
pk = self.insert(
combined_values,
pk=pk,
foreign_keys=foreign_keys,
column_order=column_order,
not_null=not_null,
defaults=defaults,
extracts=extracts,
conversions=conversions,
columns=columns,
strict=strict,
).last_pk
self.create_index(lookup_values.keys(), unique=True)
return pk
def m2m(
self,
other_table: Union[str, "Table"],
record_or_iterable: Optional[
Union[Iterable[Dict[str, Any]], Dict[str, Any]]
] = None,
pk: Optional[Union[Any, Default]] = DEFAULT,
lookup: Optional[Dict[str, Any]] = None,
m2m_table: Optional[str] = None,
alter: bool = False,
):
"""
After inserting a record in a table, create one or more records in some other
table and then create many-to-many records linking the original record and the
newly created records together.
For example::
db["dogs"].insert({"id": 1, "name": "Cleo"}, pk="id").m2m(
"humans", {"id": 1, "name": "Natalie"}, pk="id"
)
See :ref:`python_api_m2m` for details.
:param other_table: The name of the table to insert the new records into.
:param record_or_iterable: A single dictionary record to insert, or a list of records.
:param pk: The primary key to use if creating ``other_table``.
:param lookup: Same dictionary as for ``.lookup()``, to create a many-to-many lookup table.
:param m2m_table: The string name to use for the many-to-many table, defaults to creating
this automatically based on the names of the two tables.
:param alter: Set to ``True`` to add any missing columns on ``other_table`` if that table
already exists.
"""
if isinstance(other_table, str):
other_table = self.db.table(other_table, pk=pk)
our_id = self.last_pk
if lookup is not None:
if record_or_iterable is not None:
raise ValueError("Provide lookup= or record, not both")
elif record_or_iterable is None:
raise ValueError("Provide lookup= or record, not both")
tables = list(sorted([self.name, other_table.name]))
columns = ["{}_id".format(t) for t in tables]
if m2m_table is not None:
m2m_table_name = m2m_table
else:
# Detect if there is a single, unambiguous option
candidates = self.db.m2m_table_candidates(self.name, other_table.name)
if len(candidates) == 1:
m2m_table_name = candidates[0]
elif len(candidates) > 1:
raise NoObviousTable(
"No single obvious m2m table for {}, {} - use m2m_table= parameter".format(
self.name, other_table.name
)
)
else:
# If not, create a new table
m2m_table_name = m2m_table or "{}_{}".format(*tables)
m2m_table_obj = self.db.table(m2m_table_name, pk=columns, foreign_keys=columns)
if lookup is None:
# if records is only one record, put the record in a list
if isinstance(record_or_iterable, Mapping):
records = [record_or_iterable]
else:
records = cast(List, record_or_iterable)
# Ensure each record exists in other table
for record in records:
id = other_table.insert(
cast(dict, record), pk=pk, replace=True, alter=alter
).last_pk
m2m_table_obj.insert(
{
"{}_id".format(other_table.name): id,
"{}_id".format(self.name): our_id,
},
replace=True,
)
else:
id = other_table.lookup(lookup)
m2m_table_obj.insert(
{
"{}_id".format(other_table.name): id,
"{}_id".format(self.name): our_id,
},
replace=True,
)
return self
def analyze(self) -> None:
"Run ANALYZE against this table"
self.db.analyze(self.name)
def analyze_column(
self,
column: str,
common_limit: int = 10,
value_truncate=None,
total_rows=None,
most_common: bool = True,
least_common: bool = True,
) -> "ColumnDetails":
"""
Return statistics about the specified column.
See :ref:`python_api_analyze_column`.
:param column: Column to analyze
:param common_limit: Show this many column values
:param value_truncate: Truncate display of common values to this many characters
:param total_rows: Optimization - pass the total number of rows in the table to save running a fresh ``count(*)`` query
:param most_common: If ``True``, calculate the most common values
:param least_common: If ``True``, calculate the least common values
"""
db = self.db
table = self.name
if total_rows is None:
total_rows = db[table].count
def truncate(value):
if value_truncate is None or isinstance(value, (float, int)):
return value
value = str(value)
if len(value) > value_truncate:
value = value[:value_truncate] + "..."
return value
table_quoted = quote_identifier(table)
column_quoted = quote_identifier(column)
num_null = db.execute(
"select count(*) from {} where {} is null".format(
table_quoted, column_quoted
)
).fetchone()[0]
num_blank = db.execute(
"select count(*) from {} where {} = ''".format(table_quoted, column_quoted)
).fetchone()[0]
num_distinct = db.execute(
"select count(distinct {}) from {}".format(column_quoted, table_quoted)
).fetchone()[0]
most_common_results = None
least_common_results = None
if num_distinct == 1:
value = db.execute(
"select {} from {} limit 1".format(column_quoted, table_quoted)
).fetchone()[0]
most_common_results = [(truncate(value), total_rows)]
elif num_distinct != total_rows:
if most_common:
# Optimization - if all rows are null, don't run this query
if num_null == total_rows:
most_common_results = [(None, total_rows)]
else:
most_common_results = [
(truncate(r[0]), r[1])
for r in db.execute(
"select {}, count(*) from {} group by {} order by count(*) desc, {} limit {}".format(
column_quoted,
table_quoted,
column_quoted,
column_quoted,
common_limit,
)
).fetchall()
]
most_common_results.sort(key=lambda p: (p[1], p[0]), reverse=True)
if least_common:
if num_distinct <= common_limit:
# No need to run the query if it will just return the results in reverse order
least_common_results = None
else:
least_common_results = [
(truncate(r[0]), r[1])
for r in db.execute(
"select {}, count(*) from {} group by {} order by count(*), {} desc limit {}".format(
column_quoted,
table_quoted,
column_quoted,
column_quoted,
common_limit,
)
).fetchall()
]
least_common_results.sort(key=lambda p: (p[1], p[0]))
return ColumnDetails(
self.name,
column,
total_rows,
num_null,
num_blank,
num_distinct,
most_common_results,
least_common_results,
)
def add_geometry_column(
self,
column_name: str,
geometry_type: str,
srid: int = 4326,
coord_dimension: str = "XY",
not_null: bool = False,
) -> bool:
"""
In SpatiaLite, a geometry column can only be added to an existing table.
To do so, use ``table.add_geometry_column``, passing in a geometry type.
By default, this will add a nullable column using
`SRID 4326 <https://spatialreference.org/ref/epsg/wgs-84/>`__. This can
be customized using the ``column_name``, ``srid`` and ``not_null`` arguments.
Returns ``True`` if the column was successfully added, ``False`` if not.
.. code-block:: python
from sqlite_utils.db import Database
from sqlite_utils.utils import find_spatialite
db = Database("mydb.db")
db.init_spatialite(find_spatialite())
# the table must exist before adding a geometry column
table = db["locations"].create({"name": str})
table.add_geometry_column("geometry", "POINT")
:param column_name: Name of column to add
:param geometry_type: Type of geometry column, for example ``"GEOMETRY"`` or ``"POINT" or ``"POLYGON"``
:param srid: Integer SRID, defaults to 4326 for WGS84
:param coord_dimension: Dimensions to use, defaults to ``"XY"`` - set to ``"XYZ"`` to work in three dimensions
:param not_null: Should the column be ``NOT NULL``
"""
cursor = self.db.execute(
"SELECT AddGeometryColumn(?, ?, ?, ?, ?, ?);",
[
self.name,
column_name,
srid,
geometry_type,
coord_dimension,
int(not_null),
],
)
result = cursor.fetchone()
return result and bool(result[0])
def create_spatial_index(self, column_name) -> bool:
"""
A spatial index allows for significantly faster bounding box queries.
To create one, use ``create_spatial_index`` with the name of an existing geometry column.
Returns ``True`` if the index was successfully created, ``False`` if not. Calling this
function if an index already exists is a no-op.
.. code-block:: python
# assuming SpatiaLite is loaded, create the table, add the column
table = db["locations"].create({"name": str})
table.add_geometry_column("geometry", "POINT")
# now we can index it
table.create_spatial_index("geometry")
# the spatial index is a virtual table, which we can inspect
print(db["idx_locations_geometry"].schema)
# outputs:
# CREATE VIRTUAL TABLE "idx_locations_geometry" USING rtree(pkid, xmin, xmax, ymin, ymax)
:param column_name: Geometry column to create the spatial index against
"""
if f"idx_{self.name}_{column_name}" in self.db.table_names():
return False
cursor = self.db.execute(
"select CreateSpatialIndex(?, ?)", [self.name, column_name]
)
result = cursor.fetchone()
return result and bool(result[0])
class View(Queryable):
def exists(self) -> bool:
return True
def __repr__(self) -> str:
return "<View {} ({})>".format(
self.name, ", ".join(c.name for c in self.columns)
)
def drop(self, ignore: bool = False) -> None:
"""
Drop this view.
:param ignore: Set to ``True`` to ignore the error if the view does not exist
"""
try:
self.db.execute("DROP VIEW {}".format(quote_identifier(self.name)))
except sqlite3.OperationalError:
if not ignore:
raise
def jsonify_if_needed(value: object) -> object:
if isinstance(value, decimal.Decimal):
return float(value)
if isinstance(value, (dict, list, tuple)):
return json.dumps(value, default=repr, ensure_ascii=False)
elif isinstance(value, (datetime.time, datetime.date, datetime.datetime)):
return value.isoformat()
elif isinstance(value, datetime.timedelta):
return str(value)
elif isinstance(value, uuid.UUID):
return str(value)
else:
return value
def resolve_extracts(
extracts: Optional[Union[Dict[str, str], List[str], Tuple[str]]],
) -> dict:
if extracts is None:
extracts = {}
if isinstance(extracts, (list, tuple)):
extracts = {item: item for item in extracts}
return extracts
def _decode_default_value(value: str) -> object:
if value.startswith("'") and value.endswith("'"):
# It's a string
return value[1:-1]
if value.isdigit():
# It's an integer
return int(value)
if value.startswith("X'") and value.endswith("'"):
# It's a binary string, stored as hex
to_decode = value[2:-1]
return binascii.unhexlify(to_decode)
# If it is a string containing a floating point number:
try:
return float(value)
except ValueError:
pass
return value
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