Add upgrading.rst with 4.0 breaking changes documentation

Documents all breaking changes in 4.0 for both the Python library and CLI:
- db["name"] only returns tables, not views
- Default float type changed to REAL
- convert() no longer skips False values
- Table schemas use double quotes
- Upsert uses modern SQLite syntax
- Type detection now default for CSV/TSV import
- sqlite-utils tui moved to plugin
- Python 3.10+ required

docs/index.rst

@@ -41,3 +41,4 @@ Contents
    cli-reference
    contributing
    changelog
+   upgrading

docs/python-api.rst

@@ -282,11 +282,13 @@ Using this factory function allows you to set :ref:`python_api_table_configurati
 
 The ``db.table()`` method  will always return a :ref:`reference_db_table` instance, or raise a ``sqlite_utils.db.NoTable`` exception if the table name is actually a SQL view.
 
-You can also access tables or views using dictionary-style syntax, like this:
+You can also access tables using dictionary-style syntax, like this:
 
 .. code-block:: python
 
-    table_or_view = db["my_table_or_view_name"]
+    table = db["my_table_name"]
+
+This is equivalent to calling ``db.table("my_table_name")``. It will raise a ``sqlite_utils.db.NoTable`` exception if the name refers to a view rather than a table.
 
 If a table accessed using either of these methods does not yet exist, it will be created the first time you attempt to insert or upsert data into it.
 

docs/upgrading.rst

@@ -0,0 +1,134 @@
+.. _upgrading:
+
+=====================
+ Upgrading to 4.0
+=====================
+
+sqlite-utils 4.0 includes several breaking changes. This page describes what has changed and how to update your code.
+
+Python library changes
+======================
+
+db["name"] only returns tables
+------------------------------
+
+In previous versions, ``db["table_or_view_name"]`` would return either a :ref:`Table <reference_db_table>` or :ref:`View <reference_db_view>` object depending on what existed in the database.
+
+In 4.0, this syntax **only returns Table objects**. Attempting to use it with a view name will raise a ``sqlite_utils.db.NoTable`` exception.
+
+**Before (3.x):**
+
+.. code-block:: python
+
+    # This could return either a Table or View
+    obj = db["my_view"]
+    obj.drop()
+
+**After (4.0):**
+
+.. code-block:: python
+
+    # Use db.view() explicitly for views
+    view = db.view("my_view")
+    view.drop()
+
+    # db["name"] now only works with tables
+    table = db["my_table"]
+
+This change improves type safety since views lack methods like ``.insert()`` that are available on tables.
+
+db.table() raises NoTable for views
+-----------------------------------
+
+The ``db.table(name)`` method now raises ``sqlite_utils.db.NoTable`` if the name refers to a view. Use ``db.view(name)`` instead.
+
+Default floating point type is REAL
+-----------------------------------
+
+When inserting data with auto-detected column types, floating point values now create columns with type ``REAL`` instead of ``FLOAT``. ``REAL`` is the correct SQLite affinity for floating point values.
+
+This affects the schema of newly created tables but does not change how data is stored or queried.
+
+convert() no longer skips False values
+--------------------------------------
+
+The ``table.convert()`` method previously skipped rows where the column value evaluated to ``False`` (including ``0``, empty strings, and ``None``). This behavior has been removed.
+
+**Before (3.x):**
+
+.. code-block:: python
+
+    # Rows with falsey values were skipped by default
+    # --skip-false was needed to process all rows
+    table.convert("column", lambda x: x.upper(), skip_false=False)
+
+**After (4.0):**
+
+.. code-block:: python
+
+    # All rows are now processed, including those with falsey values
+    table.convert("column", lambda x: x.upper() if x else x)
+
+Table schemas use double quotes
+-------------------------------
+
+Tables created by sqlite-utils now use ``"double-quotes"`` for table and column names in the schema instead of ``[square-braces]``. Both are valid SQL, but double quotes are the SQL standard.
+
+This only affects how the schema is written. Existing tables are not modified.
+
+Upsert uses modern SQLite syntax
+--------------------------------
+
+Upsert operations now use SQLite's ``INSERT ... ON CONFLICT SET`` syntax on SQLite versions 3.24.0 and later. The previous implementation used ``INSERT OR IGNORE`` followed by ``UPDATE``.
+
+To use the old behavior, pass ``use_old_upsert=True`` to the ``Database()`` constructor:
+
+.. code-block:: python
+
+    db = Database("my.db", use_old_upsert=True)
+
+CLI changes
+===========
+
+Type detection is now the default
+---------------------------------
+
+When importing CSV or TSV data with the ``insert`` or ``upsert`` commands, sqlite-utils now automatically detects column types. Previously all columns were treated as ``TEXT`` unless ``--detect-types`` was passed.
+
+**Before (3.x):**
+
+.. code-block:: bash
+
+    # Types were detected only with --detect-types
+    sqlite-utils insert data.db mytable data.csv --csv --detect-types
+
+**After (4.0):**
+
+.. code-block:: bash
+
+    # Types are detected by default
+    sqlite-utils insert data.db mytable data.csv --csv
+
+    # Use --no-detect-types to treat all columns as TEXT
+    sqlite-utils insert data.db mytable data.csv --csv --no-detect-types
+
+The ``SQLITE_UTILS_DETECT_TYPES`` environment variable has been removed.
+
+convert --skip-false removed
+----------------------------
+
+The ``--skip-false`` option for ``sqlite-utils convert`` has been removed. All rows are now processed regardless of whether the column value is falsey.
+
+sqlite-utils tui is now a plugin
+--------------------------------
+
+The ``sqlite-utils tui`` command has been moved to a separate plugin. Install it with:
+
+.. code-block:: bash
+
+    sqlite-utils install sqlite-utils-tui
+
+Python version requirements
+===========================
+
+sqlite-utils 4.0 requires Python 3.10 or higher. Python 3.8 and 3.9 are no longer supported.

sqlite_utils/cli.py

@@ -12,6 +12,7 @@ from sqlite_utils.db import (
     BadMultiValues,
     DescIndex,
     NoTable,
+    NoView,
     quote_identifier,
 )
 from sqlite_utils.plugins import pm, get_plugins
@@ -1796,9 +1797,10 @@ def drop_view(path, view, ignore, load_extension):
     _register_db_for_cleanup(db)
     _load_extensions(db, load_extension)
     try:
-        db[view].drop(ignore=ignore)
-    except OperationalError:
-        raise click.ClickException('View "{}" does not exist'.format(view))
+        db.view(view).drop(ignore=ignore)
+    except NoView:
+        if not ignore:
+            raise click.ClickException('View "{}" does not exist'.format(view))
 
 
 @cli.command()

sqlite_utils/db.py

@@ -445,15 +445,15 @@ class Database:
         finally:
             self._tracer = prev_tracer
 
-    def __getitem__(self, table_name: str) -> Union["Table", "View"]:
+    def __getitem__(self, table_name: str) -> "Table":
         """
         ``db[table_name]`` returns a :class:`.Table` object for the table with the specified name.
         If the table does not exist yet it will be created the first time data is inserted into it.
 
+        Use ``db.view(view_name)`` to access views.
+
         :param table_name: The name of the table
         """
-        if table_name in self.view_names():
-            return self.view(table_name)
         return self.table(table_name)
 
     def __repr__(self) -> str:
@@ -1206,9 +1206,9 @@ class Database:
                     return self
                 elif replace:
                     # If SQL is the same, do nothing
-                    if create_sql == self[name].schema:
+                    if create_sql == self.view(name).schema:
                         return self
-                    self[name].drop()
+                    self.view(name).drop()
         self.execute(create_sql)
         return self
 

tests/test_cli.py

@@ -1367,7 +1367,8 @@ def test_create_view():
         )
         assert result.exit_code == 0
         assert (
-            'CREATE VIEW "version" AS select sqlite_version()' == db["version"].schema
+            'CREATE VIEW "version" AS select sqlite_version()'
+            == db.view("version").schema
         )
 
 
@@ -1404,7 +1405,7 @@ def test_create_view_ignore():
         assert result.exit_code == 0
         assert (
             'CREATE VIEW "version" AS select sqlite_version() + 1'
-            == db["version"].schema
+            == db.view("version").schema
         )
 
 
@@ -1425,7 +1426,8 @@ def test_create_view_replace():
         )
         assert result.exit_code == 0
         assert (
-            'CREATE VIEW "version" AS select sqlite_version()' == db["version"].schema
+            'CREATE VIEW "version" AS select sqlite_version()'
+            == db.view("version").schema
         )
 
 

tests/test_create.py

@@ -1082,7 +1082,7 @@ def test_drop(fresh_db):
 def test_drop_view(fresh_db):
     fresh_db.create_view("foo_view", "select 1")
     assert ["foo_view"] == fresh_db.view_names()
-    assert None is fresh_db["foo_view"].drop()
+    assert None is fresh_db.view("foo_view").drop()
     assert [] == fresh_db.view_names()
 
 
@@ -1093,7 +1093,7 @@ def test_drop_ignore(fresh_db):
     # Testing view is harder, we need to create it in order
     # to get a View object, then drop it twice
     fresh_db.create_view("foo_view", "select 1")
-    view = fresh_db["foo_view"]
+    view = fresh_db.view("foo_view")
     assert isinstance(view, View)
     view.drop()
     with pytest.raises(sqlite3.OperationalError):

tests/test_fts.py

@@ -424,7 +424,7 @@ def test_enable_fts_error_message_on_views():
     db = Database(memory=True)
     db.create_view("hello", "select 1 + 1")
     with pytest.raises(NotImplementedError) as e:
-        db["hello"].enable_fts()  # type: ignore[call-arg]
+        db.view("hello").enable_fts()  # type: ignore[call-arg]
         assert e.value.args[0] == "enable_fts() is supported on tables but not on views"
 
 

tests/test_tracer.py

@@ -15,7 +15,6 @@ def test_tracer():
         ("select name from sqlite_master where type = 'view'", None),
         ("select name from sqlite_master where type = 'table'", None),
         ("select name from sqlite_master where type = 'view'", None),
-        ("select name from sqlite_master where type = 'view'", None),
         ("select name from sqlite_master where type = 'table'", None),
         ("select name from sqlite_master where type = 'view'", None),
         ('CREATE TABLE "dogs" (\n   "name" TEXT\n);\n        ', None),