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[3.10] gh-94628: Add explicit parameter list to sqlite3.connect docs (GH-94629) (#94646)
Co-authored-by: CAM Gerlach <CAM.Gerlach@Gerlach.CAM>.
(cherry picked from commit 3eb2b9634f)
Co-authored-by: Erlend Egeberg Aasland <erlend.aasland@protonmail.com>
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Erlend Egeberg Aasland
GitHub
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1 changed files with 94 additions and 65 deletions
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@ -218,90 +218,89 @@ Module functions and constants
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(bitwise or) operator.
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.. function:: connect(database[, timeout, detect_types, isolation_level, check_same_thread, factory, cached_statements, uri])
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Opens a connection to the SQLite database file *database*. By default returns a
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:class:`Connection` object, unless a custom *factory* is given.
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.. function:: connect(database, timeout=5.0, detect_types=0, isolation_level="DEFERRED", check_same_thread=True, factory=sqlite3.Connection, cached_statements=128, uri=False)
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*database* is a :term:`path-like object` giving the pathname (absolute or
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relative to the current working directory) of the database file to be opened.
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You can use ``":memory:"`` to open a database connection to a database that
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resides in RAM instead of on disk.
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Open a connection to an SQLite database.
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When a database is accessed by multiple connections, and one of the processes
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modifies the database, the SQLite database is locked until that transaction is
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committed. The *timeout* parameter specifies how long the connection should wait
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for the lock to go away until raising an exception. The default for the timeout
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parameter is 5.0 (five seconds).
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:param database:
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The path to the database file to be opened.
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Pass ``":memory:"`` to open a connection to a database that is
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in RAM instead of on disk.
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:type database: :term:`path-like object`
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For the *isolation_level* parameter, please see the
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:attr:`~Connection.isolation_level` property of :class:`Connection` objects.
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:param timeout:
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How many seconds the connection should wait before raising
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an exception, if the database is locked by another connection.
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If another connection opens a transaction to modify the database,
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it will be locked until that transaction is committed.
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Default five seconds.
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:type timeout: float
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SQLite natively supports only the types TEXT, INTEGER, REAL, BLOB and NULL. If
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you want to use other types you must add support for them yourself. The
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*detect_types* parameter and using custom **converters** registered with the
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module-level :func:`register_converter` function allow you to easily do that.
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*detect_types* defaults to 0 (type detection disabled).
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:param detect_types:
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Control whether and how data types not
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:ref:`natively supported by SQLite <sqlite3-types>`
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are looked up to be converted to Python types,
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using the converters registered with :func:`register_converter`.
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Set it to any combination (using ``|``, bitwise or) of
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:const:`PARSE_DECLTYPES` and :const:`PARSE_COLNAMES`
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to enable type detection.
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to enable this.
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Column names takes precedence over declared types if both flags are set.
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Types cannot be detected for generated fields (for example ``max(data)``),
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even when the *detect_types* parameter is set.
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In such cases, the returned type is :class:`str`.
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even when the *detect_types* parameter is set; :class:`str` will be
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returned instead.
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By default (``0``), type detection is disabled.
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:type detect_types: int
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By default, *check_same_thread* is :const:`True` and only the creating thread may
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use the connection. If set :const:`False`, the returned connection may be shared
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across multiple threads. When using multiple threads with the same connection
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writing operations should be serialized by the user to avoid data corruption.
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:param isolation_level:
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The :attr:`~Connection.isolation_level` of the connection,
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controlling whether and how transactions are implicitly opened.
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Can be ``"DEFERRED"`` (default), ``"EXCLUSIVE"`` or ``"IMMEDIATE"``;
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or :const:`None` to disable opening transactions implicitly.
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See :ref:`sqlite3-controlling-transactions` for more.
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:type isolation_level: str | None
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By default, the :mod:`sqlite3` module uses its :class:`Connection` class for the
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connect call. You can, however, subclass the :class:`Connection` class and make
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:func:`connect` use your class instead by providing your class for the *factory*
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parameter.
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:param check_same_thread:
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If :const:`True` (default), only the creating thread may use the connection.
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If :const:`False`, the connection may be shared across multiple threads;
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if so, write operations should be serialized by the user to avoid data
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corruption.
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:type check_same_thread: bool
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Consult the section :ref:`sqlite3-types` of this manual for details.
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:param factory:
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A custom subclass of :class:`Connection` to create the connection with,
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if not the default :class:`Connection` class.
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:type factory: :class:`Connection`
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The :mod:`sqlite3` module internally uses a statement cache to avoid SQL parsing
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overhead. If you want to explicitly set the number of statements that are cached
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for the connection, you can set the *cached_statements* parameter. The currently
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implemented default is to cache 100 statements.
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:param cached_statements:
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The number of statements that ``sqlite3``
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should internally cache for this connection, to avoid parsing overhead.
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By default, 100 statements.
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:type cached_statements: int
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If *uri* is :const:`True`, *database* is interpreted as a
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:abbr:`URI (Uniform Resource Identifier)` with a file path and an optional
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query string. The scheme part *must* be ``"file:"``. The path can be a
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relative or absolute file path. The query string allows us to pass
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parameters to SQLite. Some useful URI tricks include::
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:param uri:
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If set to :const:`True`, *database* is interpreted as a
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:abbr:`URI (Uniform Resource Identifier)` with a file path
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and an optional query string.
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The scheme part *must* be ``"file:"``,
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and the path can be relative or absolute.
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The query string allows passing parameters to SQLite,
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enabling various :ref:`sqlite3-uri-tricks`.
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:type uri: bool
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# Open a database in read-only mode.
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con = sqlite3.connect("file:template.db?mode=ro", uri=True)
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# Don't implicitly create a new database file if it does not already exist.
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# Will raise sqlite3.OperationalError if unable to open a database file.
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con = sqlite3.connect("file:nosuchdb.db?mode=rw", uri=True)
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# Create a shared named in-memory database.
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con1 = sqlite3.connect("file:mem1?mode=memory&cache=shared", uri=True)
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con2 = sqlite3.connect("file:mem1?mode=memory&cache=shared", uri=True)
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con1.executescript("create table t(t); insert into t values(28);")
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rows = con2.execute("select * from t").fetchall()
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More information about this feature, including a list of recognized
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parameters, can be found in the
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`SQLite URI documentation <https://www.sqlite.org/uri.html>`_.
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:rtype: sqlite3.Connection
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.. audit-event:: sqlite3.connect database sqlite3.connect
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.. audit-event:: sqlite3.connect/handle connection_handle sqlite3.connect
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.. versionchanged:: 3.4
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Added the *uri* parameter.
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.. versionadded:: 3.4
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The *uri* parameter.
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.. versionchanged:: 3.7
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*database* can now also be a :term:`path-like object`, not only a string.
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.. versionchanged:: 3.10
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Added the ``sqlite3.connect/handle`` auditing event.
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.. versionadded:: 3.10
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The ``sqlite3.connect/handle`` auditing event.
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.. function:: register_converter(typename, converter, /)
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@ -1238,6 +1237,36 @@ regardless of the value of :attr:`~Connection.isolation_level`.
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https://www.sqlite.org/lang_transaction.html#deferred_immediate_and_exclusive_transactions
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.. _sqlite3-uri-tricks:
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SQLite URI tricks
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-----------------
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Some useful URI tricks include:
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* Open a database in read-only mode::
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con = sqlite3.connect("file:template.db?mode=ro", uri=True)
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* Do not implicitly create a new database file if it does not already exist;
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will raise :exc:`~sqlite3.OperationalError` if unable to create a new file::
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con = sqlite3.connect("file:nosuchdb.db?mode=rw", uri=True)
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* Create a shared named in-memory database::
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con1 = sqlite3.connect("file:mem1?mode=memory&cache=shared", uri=True)
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con2 = sqlite3.connect("file:mem1?mode=memory&cache=shared", uri=True)
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con1.execute("create table t(t)")
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con1.execute("insert into t values(28)")
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con1.commit()
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rows = con2.execute("select * from t").fetchall()
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More information about this feature, including a list of parameters,
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can be found in the `SQLite URI documentation`_.
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.. _SQLite URI documentation: https://www.sqlite.org/uri.html
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Using :mod:`sqlite3` efficiently
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--------------------------------
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