TSV and JSON support for sqlite-utils memory

Closes #281, closes #279, refs #272
This commit is contained in:
Simon Willison 2021-06-18 20:11:54 -07:00
commit 00e4bd5ff1
4 changed files with 191 additions and 26 deletions

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@ -234,21 +234,21 @@ This example attaches the ``books.db`` database under the alias ``books`` and th
sqlite-utils dogs.db --attach books books.db \
'select * from sqlite_master union all select * from books.sqlite_master'
.. _cli_query_memory:
.. _cli_memory:
Querying CSV data directly using an in-memory database
======================================================
Querying data directly using an in-memory database
==================================================
The ``sqlite-utils memory`` command works similar to ``sqlite-utils query``, but allows you to execute queries against an in-memory database.
You can also pass this command CSV files which will be loaded into a temporary in-memory table, allowing you to execute SQL against that data without a separate step to first convert it to SQLite.
You can also pass this command CSV or JSON files which will be loaded into a temporary in-memory table, allowing you to execute SQL against that data without a separate step to first convert it to SQLite.
Without any extra arguments, this command executes SQL against the in-memory database directly::
$ sqlite-utils memory 'select sqlite_version()'
[{"sqlite_version()": "3.35.5"}]
It takes all of the same formatting options as :ref:`sqlite-utils query <cli_query>`: ``--csv`` and ``--csv`` and ``--table`` and ``--nl``::
It takes all of the same output formatting options as :ref:`sqlite-utils query <cli_query>`: ``--csv`` and ``--csv`` and ``--table`` and ``--nl``::
$ sqlite-utils memory 'select sqlite_version()' --csv
sqlite_version()
@ -260,24 +260,28 @@ It takes all of the same formatting options as :ref:`sqlite-utils query <cli_que
| 3.35.5 |
+--------------------+
.. _cli_query_memory_csv:
.. _cli_memory_csv_json:
Running queries directly against CSV
------------------------------------
Running queries directly against CSV or JSON
--------------------------------------------
If you have data in CSV format you can load it into an in-memory SQLite database and run queries against it directly in a single command using ``sqlite-utils memory`` like this::
If you have data in CSV or JSON format you can load it into an in-memory SQLite database and run queries against it directly in a single command using ``sqlite-utils memory`` like this::
$ sqlite-utils memory data.csv "select * from data"
You can pass multiple files to the command if you want to run joins between different CSV files::
You can pass multiple files to the command if you want to run joins between data from different files::
$ sqlite-utils memory one.csv two.csv "select * from one join two on one.id = two.other_id"
$ sqlite-utils memory one.csv two.json "select * from one join two on one.id = two.other_id"
The in-memory tables will be named after the CSV files without their ``.csv`` extension. The tool also sets up aliases for those tables (using SQL views) as ``t1``, ``t2`` and so on, or you can use the alias ``t`` to refer to the first table::
If your data is JSON it should be the same format supported by the :ref:`sqlite-utils insert command <cli_inserting_data>` - so either a single JSON object (treated as a single row) or a list of JSON objects.
CSV data can be comma- or tab- delimited.
The in-memory tables will be named after the files without their extensions. The tool also sets up aliases for those tables (using SQL views) as ``t1``, ``t2`` and so on, or you can use the alias ``t`` to refer to the first table::
$ sqlite-utils memory example.csv "select * from t"
To read from standard input, use ``-`` as the filename - then use ``stdin`` or ``t`` or ``t1`` as the table name::
To read from standard input, use either ``-`` or ``stdin`` as the filename - then use ``stdin`` or ``t`` or ``t1`` as the table name::
$ cat example.csv | sqlite-utils memory - "select * from stdin"
@ -287,7 +291,24 @@ Incoming CSV data will be assumed to use ``utf-8``. If your data uses a differen
If you are joining across multiple CSV files they must all use the same encoding.
.. _cli_query_memory_attach:
.. _cli_memory_explicit:
Explicitly specifying the format
--------------------------------
By default, ``sqlite-utils memory`` will attempt to detect the incoming data format (JSON, TSV or CSV) automatically.
You can instead specify an explicit format by adding a ``:csv``, ``:tsv``, ``:json`` or ``:nl`` (for newline-delimited JSON) suffix to the filename. For example::
$ sqlite-utils memory one.dat:csv two.dat:nl "select * from one union select * from two"
Here the contents of ``one.dat`` will be treated as CSV and the contents of ``two.dat`` will be treated as newline-delimited JSON.
To explicitly specify the format for data piped into the tool on standard input, use ``stdin:format`` - for example::
$ cat one.dat | sqlite-utils memory stdin:csv "select * from stdin"
.. _cli_memory_attach:
Joining in-memory data against existing databases using \-\-attach
------------------------------------------------------------------
@ -303,7 +324,7 @@ Here the ``--attach trees trees.db`` option makes the ``trees.db`` database avai
The CSV data that was piped into the script is available in the ``stdin`` table, so ``... where rowid in (select id from stdin)`` can be used to return rows from the ``trees`` table that match IDs that were piped in as CSV content.
.. _cli_query_memory_dump_save:
.. _cli_memory_dump_save:
\-\-dump and \-\-save
---------------------

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@ -14,7 +14,14 @@ import os
import sys
import csv as csv_std
import tabulate
from .utils import file_progress, find_spatialite, sqlite3, decode_base64_values
from .utils import (
file_progress,
find_spatialite,
sqlite3,
decode_base64_values,
rows_from_file,
Format,
)
CONTEXT_SETTINGS = dict(help_option_names=["-h", "--help"])
@ -1175,18 +1182,21 @@ def memory(
paths = [sql]
sql = None
for i, path in enumerate(paths):
if path == "-":
# Path may have a :format suffix
if ":" in path and path.rsplit(":", 1)[-1].upper() in Format.__members__:
path, suffix = path.rsplit(":", 1)
format = Format[suffix.upper()]
else:
format = None
if path in ("-", "stdin"):
csv_fp = sys.stdin.buffer
csv_table = "stdin"
else:
csv_path = pathlib.Path(path)
csv_table = csv_path.stem
csv_fp = csv_path.open("rb")
encoding = encoding or "utf-8-sig"
decoded_fp = io.TextIOWrapper(csv_fp, encoding=encoding)
db[csv_table].insert_all(csv_std.DictReader(decoded_fp))
rows = rows_from_file(csv_fp, format=format, encoding=encoding)
db[csv_table].insert_all(rows, alter=True)
# Add convenient t / t1 / t2 views
view_names = ["t{}".format(i + 1)]
if i == 0:

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@ -1,8 +1,13 @@
import base64
import click
import contextlib
import csv
import enum
import io
import json
import os
from typing import Generator
import click
try:
import pysqlite3 as sqlite3
@ -111,3 +116,58 @@ def file_progress(file, silent=False, **kwargs):
file_length = os.path.getsize(file.name)
with click.progressbar(length=file_length, **kwargs) as bar:
yield UpdateWrapper(file, bar.update)
class Format(enum.Enum):
CSV = 1
TSV = 2
JSON = 3
NL = 4
class RowsFromFileError(Exception):
pass
class RowsFromFileBadJSON(RowsFromFileError):
pass
def rows_from_file(
fp,
format=None,
dialect=None,
encoding=None,
) -> Generator[dict, None, None]:
if format == Format.JSON:
decoded = json.load(fp)
if isinstance(decoded, dict):
decoded = [decoded]
if not isinstance(decoded, list):
raise RowsFromFileBadJSON("JSON must be a list or a dictionary")
yield from decoded
elif format == Format.NL:
yield from (json.loads(line) for line in fp if line.strip())
elif format == Format.CSV:
decoded_fp = io.TextIOWrapper(fp, encoding=encoding or "utf-8-sig")
yield from csv.DictReader(decoded_fp, dialect=dialect)
elif format == Format.TSV:
yield from rows_from_file(
fp, format=Format.CSV, dialect=csv.excel_tab, encoding=encoding
)
elif format is None:
# Detect the format, then call this recursively
buffered = io.BufferedReader(fp, buffer_size=4096)
first_bytes = buffered.peek(2048).strip()
if first_bytes.startswith(b"[") or first_bytes.startswith(b"{"):
# TODO: Detect newline-JSON
yield from rows_from_file(buffered, format=Format.JSON)
else:
dialect = csv.Sniffer().sniff(
first_bytes.decode(encoding or "utf-8-sig", "ignore")
)
yield from rows_from_file(
buffered, format=Format.CSV, dialect=dialect, encoding=encoding
)
else:
raise RowsFromFileError("Bad format")

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@ -1,8 +1,10 @@
from sqlite_utils import cli, Database
from click.testing import CliRunner
import pytest
import json
import pytest
from click.testing import CliRunner
from sqlite_utils import Database, cli
def test_memory_basic():
result = CliRunner().invoke(cli.cli, ["memory", "select 1 + 1"])
@ -35,6 +37,78 @@ def test_memory_csv(tmpdir, sql_from, use_stdin):
)
@pytest.mark.parametrize("use_stdin", (True, False))
def test_memory_tsv(tmpdir, use_stdin):
data = "id\tname\n1\tCleo\n2\tBants"
if use_stdin:
input = data
path = "stdin:tsv"
sql_from = "stdin"
else:
input = None
path = str(tmpdir / "chickens.tsv")
open(path, "w").write(data)
path = path + ":tsv"
sql_from = "chickens"
result = CliRunner().invoke(
cli.cli,
["memory", path, "select * from {}".format(sql_from)],
input=data,
)
assert result.exit_code == 0, result.output
assert json.loads(result.output.strip()) == [
{"id": "1", "name": "Cleo"},
{"id": "2", "name": "Bants"},
]
@pytest.mark.parametrize("use_stdin", (True, False))
def test_memory_json(tmpdir, use_stdin):
data = '[{"name": "Bants"}, {"name": "Dori", "age": 1}]'
if use_stdin:
input = data
path = "stdin:json"
sql_from = "stdin"
else:
input = None
path = str(tmpdir / "chickens.json")
open(path, "w").write(data)
path = path + ":json"
sql_from = "chickens"
result = CliRunner().invoke(
cli.cli,
["memory", path, "select * from {}".format(sql_from)],
input=input,
)
assert result.exit_code == 0, result.output
assert json.loads(result.output.strip()) == [
{"name": "Bants", "age": None},
{"name": "Dori", "age": 1},
]
@pytest.mark.parametrize("use_stdin", (True, False))
def test_memory_json_nl(tmpdir, use_stdin):
data = '{"name": "Bants"}\n\n{"name": "Dori"}'
if use_stdin:
input = data
path = "stdin:nl"
sql_from = "stdin"
else:
input = None
path = str(tmpdir / "chickens.json")
open(path, "w").write(data)
path = path + ":nl"
sql_from = "chickens"
result = CliRunner().invoke(
cli.cli,
["memory", path, "select * from {}".format(sql_from)],
input=data,
)
assert result.exit_code == 0, result.output
assert json.loads(result.output.strip()) == [{"name": "Bants"}, {"name": "Dori"}]
@pytest.mark.parametrize("use_stdin", (True, False))
def test_memory_csv_encoding(tmpdir, use_stdin):
latin1_csv = (