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diff --git a/lib/sqlalchemy/engine/events.py b/lib/sqlalchemy/engine/events.py new file mode 100644 index 0000000..286c4d4 --- /dev/null +++ b/lib/sqlalchemy/engine/events.py @@ -0,0 +1,835 @@ +# sqlalchemy/engine/events.py +# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors +# <see AUTHORS file> +# +# This module is part of SQLAlchemy and is released under +# the MIT License: https://www.opensource.org/licenses/mit-license.php + + +from .base import Engine +from .interfaces import Connectable +from .interfaces import Dialect +from .. import event +from .. import exc + + +class ConnectionEvents(event.Events): + """Available events for :class:`.Connectable`, which includes + :class:`_engine.Connection` and :class:`_engine.Engine`. + + The methods here define the name of an event as well as the names of + members that are passed to listener functions. + + An event listener can be associated with any :class:`.Connectable` + class or instance, such as an :class:`_engine.Engine`, e.g.:: + + from sqlalchemy import event, create_engine + + def before_cursor_execute(conn, cursor, statement, parameters, context, + executemany): + log.info("Received statement: %s", statement) + + engine = create_engine('postgresql://scott:tiger@localhost/test') + event.listen(engine, "before_cursor_execute", before_cursor_execute) + + or with a specific :class:`_engine.Connection`:: + + with engine.begin() as conn: + @event.listens_for(conn, 'before_cursor_execute') + def before_cursor_execute(conn, cursor, statement, parameters, + context, executemany): + log.info("Received statement: %s", statement) + + When the methods are called with a `statement` parameter, such as in + :meth:`.after_cursor_execute` or :meth:`.before_cursor_execute`, + the statement is the exact SQL string that was prepared for transmission + to the DBAPI ``cursor`` in the connection's :class:`.Dialect`. + + The :meth:`.before_execute` and :meth:`.before_cursor_execute` + events can also be established with the ``retval=True`` flag, which + allows modification of the statement and parameters to be sent + to the database. The :meth:`.before_cursor_execute` event is + particularly useful here to add ad-hoc string transformations, such + as comments, to all executions:: + + from sqlalchemy.engine import Engine + from sqlalchemy import event + + @event.listens_for(Engine, "before_cursor_execute", retval=True) + def comment_sql_calls(conn, cursor, statement, parameters, + context, executemany): + statement = statement + " -- some comment" + return statement, parameters + + .. note:: :class:`_events.ConnectionEvents` can be established on any + combination of :class:`_engine.Engine`, :class:`_engine.Connection`, + as well + as instances of each of those classes. Events across all + four scopes will fire off for a given instance of + :class:`_engine.Connection`. However, for performance reasons, the + :class:`_engine.Connection` object determines at instantiation time + whether or not its parent :class:`_engine.Engine` has event listeners + established. Event listeners added to the :class:`_engine.Engine` + class or to an instance of :class:`_engine.Engine` + *after* the instantiation + of a dependent :class:`_engine.Connection` instance will usually + *not* be available on that :class:`_engine.Connection` instance. + The newly + added listeners will instead take effect for + :class:`_engine.Connection` + instances created subsequent to those event listeners being + established on the parent :class:`_engine.Engine` class or instance. + + :param retval=False: Applies to the :meth:`.before_execute` and + :meth:`.before_cursor_execute` events only. When True, the + user-defined event function must have a return value, which + is a tuple of parameters that replace the given statement + and parameters. See those methods for a description of + specific return arguments. + + """ + + _target_class_doc = "SomeEngine" + _dispatch_target = Connectable + + @classmethod + def _listen(cls, event_key, retval=False): + target, identifier, fn = ( + event_key.dispatch_target, + event_key.identifier, + event_key._listen_fn, + ) + + target._has_events = True + + if not retval: + if identifier == "before_execute": + orig_fn = fn + + def wrap_before_execute( + conn, clauseelement, multiparams, params, execution_options + ): + orig_fn( + conn, + clauseelement, + multiparams, + params, + execution_options, + ) + return clauseelement, multiparams, params + + fn = wrap_before_execute + elif identifier == "before_cursor_execute": + orig_fn = fn + + def wrap_before_cursor_execute( + conn, cursor, statement, parameters, context, executemany + ): + orig_fn( + conn, + cursor, + statement, + parameters, + context, + executemany, + ) + return statement, parameters + + fn = wrap_before_cursor_execute + elif retval and identifier not in ( + "before_execute", + "before_cursor_execute", + "handle_error", + ): + raise exc.ArgumentError( + "Only the 'before_execute', " + "'before_cursor_execute' and 'handle_error' engine " + "event listeners accept the 'retval=True' " + "argument." + ) + event_key.with_wrapper(fn).base_listen() + + @event._legacy_signature( + "1.4", + ["conn", "clauseelement", "multiparams", "params"], + lambda conn, clauseelement, multiparams, params, execution_options: ( + conn, + clauseelement, + multiparams, + params, + ), + ) + def before_execute( + self, conn, clauseelement, multiparams, params, execution_options + ): + """Intercept high level execute() events, receiving uncompiled + SQL constructs and other objects prior to rendering into SQL. + + This event is good for debugging SQL compilation issues as well + as early manipulation of the parameters being sent to the database, + as the parameter lists will be in a consistent format here. + + This event can be optionally established with the ``retval=True`` + flag. The ``clauseelement``, ``multiparams``, and ``params`` + arguments should be returned as a three-tuple in this case:: + + @event.listens_for(Engine, "before_execute", retval=True) + def before_execute(conn, clauseelement, multiparams, params): + # do something with clauseelement, multiparams, params + return clauseelement, multiparams, params + + :param conn: :class:`_engine.Connection` object + :param clauseelement: SQL expression construct, :class:`.Compiled` + instance, or string statement passed to + :meth:`_engine.Connection.execute`. + :param multiparams: Multiple parameter sets, a list of dictionaries. + :param params: Single parameter set, a single dictionary. + :param execution_options: dictionary of execution + options passed along with the statement, if any. This is a merge + of all options that will be used, including those of the statement, + the connection, and those passed in to the method itself for + the 2.0 style of execution. + + .. versionadded: 1.4 + + .. seealso:: + + :meth:`.before_cursor_execute` + + """ + + @event._legacy_signature( + "1.4", + ["conn", "clauseelement", "multiparams", "params", "result"], + lambda conn, clauseelement, multiparams, params, execution_options, result: ( # noqa + conn, + clauseelement, + multiparams, + params, + result, + ), + ) + def after_execute( + self, + conn, + clauseelement, + multiparams, + params, + execution_options, + result, + ): + """Intercept high level execute() events after execute. + + + :param conn: :class:`_engine.Connection` object + :param clauseelement: SQL expression construct, :class:`.Compiled` + instance, or string statement passed to + :meth:`_engine.Connection.execute`. + :param multiparams: Multiple parameter sets, a list of dictionaries. + :param params: Single parameter set, a single dictionary. + :param execution_options: dictionary of execution + options passed along with the statement, if any. This is a merge + of all options that will be used, including those of the statement, + the connection, and those passed in to the method itself for + the 2.0 style of execution. + + .. versionadded: 1.4 + + :param result: :class:`_engine.CursorResult` generated by the + execution. + + """ + + def before_cursor_execute( + self, conn, cursor, statement, parameters, context, executemany + ): + """Intercept low-level cursor execute() events before execution, + receiving the string SQL statement and DBAPI-specific parameter list to + be invoked against a cursor. + + This event is a good choice for logging as well as late modifications + to the SQL string. It's less ideal for parameter modifications except + for those which are specific to a target backend. + + This event can be optionally established with the ``retval=True`` + flag. The ``statement`` and ``parameters`` arguments should be + returned as a two-tuple in this case:: + + @event.listens_for(Engine, "before_cursor_execute", retval=True) + def before_cursor_execute(conn, cursor, statement, + parameters, context, executemany): + # do something with statement, parameters + return statement, parameters + + See the example at :class:`_events.ConnectionEvents`. + + :param conn: :class:`_engine.Connection` object + :param cursor: DBAPI cursor object + :param statement: string SQL statement, as to be passed to the DBAPI + :param parameters: Dictionary, tuple, or list of parameters being + passed to the ``execute()`` or ``executemany()`` method of the + DBAPI ``cursor``. In some cases may be ``None``. + :param context: :class:`.ExecutionContext` object in use. May + be ``None``. + :param executemany: boolean, if ``True``, this is an ``executemany()`` + call, if ``False``, this is an ``execute()`` call. + + .. seealso:: + + :meth:`.before_execute` + + :meth:`.after_cursor_execute` + + """ + + def after_cursor_execute( + self, conn, cursor, statement, parameters, context, executemany + ): + """Intercept low-level cursor execute() events after execution. + + :param conn: :class:`_engine.Connection` object + :param cursor: DBAPI cursor object. Will have results pending + if the statement was a SELECT, but these should not be consumed + as they will be needed by the :class:`_engine.CursorResult`. + :param statement: string SQL statement, as passed to the DBAPI + :param parameters: Dictionary, tuple, or list of parameters being + passed to the ``execute()`` or ``executemany()`` method of the + DBAPI ``cursor``. In some cases may be ``None``. + :param context: :class:`.ExecutionContext` object in use. May + be ``None``. + :param executemany: boolean, if ``True``, this is an ``executemany()`` + call, if ``False``, this is an ``execute()`` call. + + """ + + def handle_error(self, exception_context): + r"""Intercept all exceptions processed by the + :class:`_engine.Connection`. + + This includes all exceptions emitted by the DBAPI as well as + within SQLAlchemy's statement invocation process, including + encoding errors and other statement validation errors. Other areas + in which the event is invoked include transaction begin and end, + result row fetching, cursor creation. + + Note that :meth:`.handle_error` may support new kinds of exceptions + and new calling scenarios at *any time*. Code which uses this + event must expect new calling patterns to be present in minor + releases. + + To support the wide variety of members that correspond to an exception, + as well as to allow extensibility of the event without backwards + incompatibility, the sole argument received is an instance of + :class:`.ExceptionContext`. This object contains data members + representing detail about the exception. + + Use cases supported by this hook include: + + * read-only, low-level exception handling for logging and + debugging purposes + * exception re-writing + * Establishing or disabling whether a connection or the owning + connection pool is invalidated or expired in response to a + specific exception [1]_. + + The hook is called while the cursor from the failed operation + (if any) is still open and accessible. Special cleanup operations + can be called on this cursor; SQLAlchemy will attempt to close + this cursor subsequent to this hook being invoked. If the connection + is in "autocommit" mode, the transaction also remains open within + the scope of this hook; the rollback of the per-statement transaction + also occurs after the hook is called. + + .. note:: + + .. [1] The pool "pre_ping" handler enabled using the + :paramref:`_sa.create_engine.pool_pre_ping` parameter does + **not** consult this event before deciding if the "ping" + returned false, as opposed to receiving an unhandled error. + For this use case, the :ref:`legacy recipe based on + engine_connect() may be used + <pool_disconnects_pessimistic_custom>`. A future API allow + more comprehensive customization of the "disconnect" + detection mechanism across all functions. + + A handler function has two options for replacing + the SQLAlchemy-constructed exception into one that is user + defined. It can either raise this new exception directly, in + which case all further event listeners are bypassed and the + exception will be raised, after appropriate cleanup as taken + place:: + + @event.listens_for(Engine, "handle_error") + def handle_exception(context): + if isinstance(context.original_exception, + psycopg2.OperationalError) and \ + "failed" in str(context.original_exception): + raise MySpecialException("failed operation") + + .. warning:: Because the + :meth:`_events.ConnectionEvents.handle_error` + event specifically provides for exceptions to be re-thrown as + the ultimate exception raised by the failed statement, + **stack traces will be misleading** if the user-defined event + handler itself fails and throws an unexpected exception; + the stack trace may not illustrate the actual code line that + failed! It is advised to code carefully here and use + logging and/or inline debugging if unexpected exceptions are + occurring. + + Alternatively, a "chained" style of event handling can be + used, by configuring the handler with the ``retval=True`` + modifier and returning the new exception instance from the + function. In this case, event handling will continue onto the + next handler. The "chained" exception is available using + :attr:`.ExceptionContext.chained_exception`:: + + @event.listens_for(Engine, "handle_error", retval=True) + def handle_exception(context): + if context.chained_exception is not None and \ + "special" in context.chained_exception.message: + return MySpecialException("failed", + cause=context.chained_exception) + + Handlers that return ``None`` may be used within the chain; when + a handler returns ``None``, the previous exception instance, + if any, is maintained as the current exception that is passed onto the + next handler. + + When a custom exception is raised or returned, SQLAlchemy raises + this new exception as-is, it is not wrapped by any SQLAlchemy + object. If the exception is not a subclass of + :class:`sqlalchemy.exc.StatementError`, + certain features may not be available; currently this includes + the ORM's feature of adding a detail hint about "autoflush" to + exceptions raised within the autoflush process. + + :param context: an :class:`.ExceptionContext` object. See this + class for details on all available members. + + .. versionadded:: 0.9.7 Added the + :meth:`_events.ConnectionEvents.handle_error` hook. + + .. versionchanged:: 1.1 The :meth:`.handle_error` event will now + receive all exceptions that inherit from ``BaseException``, + including ``SystemExit`` and ``KeyboardInterrupt``. The setting for + :attr:`.ExceptionContext.is_disconnect` is ``True`` in this case and + the default for + :attr:`.ExceptionContext.invalidate_pool_on_disconnect` is + ``False``. + + .. versionchanged:: 1.0.0 The :meth:`.handle_error` event is now + invoked when an :class:`_engine.Engine` fails during the initial + call to :meth:`_engine.Engine.connect`, as well as when a + :class:`_engine.Connection` object encounters an error during a + reconnect operation. + + .. versionchanged:: 1.0.0 The :meth:`.handle_error` event is + not fired off when a dialect makes use of the + ``skip_user_error_events`` execution option. This is used + by dialects which intend to catch SQLAlchemy-specific exceptions + within specific operations, such as when the MySQL dialect detects + a table not present within the ``has_table()`` dialect method. + Prior to 1.0.0, code which implements :meth:`.handle_error` needs + to ensure that exceptions thrown in these scenarios are re-raised + without modification. + + """ + + def engine_connect(self, conn, branch): + """Intercept the creation of a new :class:`_engine.Connection`. + + This event is called typically as the direct result of calling + the :meth:`_engine.Engine.connect` method. + + It differs from the :meth:`_events.PoolEvents.connect` method, which + refers to the actual connection to a database at the DBAPI level; + a DBAPI connection may be pooled and reused for many operations. + In contrast, this event refers only to the production of a higher level + :class:`_engine.Connection` wrapper around such a DBAPI connection. + + It also differs from the :meth:`_events.PoolEvents.checkout` event + in that it is specific to the :class:`_engine.Connection` object, + not the + DBAPI connection that :meth:`_events.PoolEvents.checkout` deals with, + although + this DBAPI connection is available here via the + :attr:`_engine.Connection.connection` attribute. + But note there can in fact + be multiple :meth:`_events.PoolEvents.checkout` + events within the lifespan + of a single :class:`_engine.Connection` object, if that + :class:`_engine.Connection` + is invalidated and re-established. There can also be multiple + :class:`_engine.Connection` + objects generated for the same already-checked-out + DBAPI connection, in the case that a "branch" of a + :class:`_engine.Connection` + is produced. + + :param conn: :class:`_engine.Connection` object. + :param branch: if True, this is a "branch" of an existing + :class:`_engine.Connection`. A branch is generated within the course + of a statement execution to invoke supplemental statements, most + typically to pre-execute a SELECT of a default value for the purposes + of an INSERT statement. + + .. seealso:: + + :meth:`_events.PoolEvents.checkout` + the lower-level pool checkout event + for an individual DBAPI connection + + """ + + def set_connection_execution_options(self, conn, opts): + """Intercept when the :meth:`_engine.Connection.execution_options` + method is called. + + This method is called after the new :class:`_engine.Connection` + has been + produced, with the newly updated execution options collection, but + before the :class:`.Dialect` has acted upon any of those new options. + + Note that this method is not called when a new + :class:`_engine.Connection` + is produced which is inheriting execution options from its parent + :class:`_engine.Engine`; to intercept this condition, use the + :meth:`_events.ConnectionEvents.engine_connect` event. + + :param conn: The newly copied :class:`_engine.Connection` object + + :param opts: dictionary of options that were passed to the + :meth:`_engine.Connection.execution_options` method. + + .. versionadded:: 0.9.0 + + .. seealso:: + + :meth:`_events.ConnectionEvents.set_engine_execution_options` + - event + which is called when :meth:`_engine.Engine.execution_options` + is called. + + + """ + + def set_engine_execution_options(self, engine, opts): + """Intercept when the :meth:`_engine.Engine.execution_options` + method is called. + + The :meth:`_engine.Engine.execution_options` method produces a shallow + copy of the :class:`_engine.Engine` which stores the new options. + That new + :class:`_engine.Engine` is passed here. + A particular application of this + method is to add a :meth:`_events.ConnectionEvents.engine_connect` + event + handler to the given :class:`_engine.Engine` + which will perform some per- + :class:`_engine.Connection` task specific to these execution options. + + :param conn: The newly copied :class:`_engine.Engine` object + + :param opts: dictionary of options that were passed to the + :meth:`_engine.Connection.execution_options` method. + + .. versionadded:: 0.9.0 + + .. seealso:: + + :meth:`_events.ConnectionEvents.set_connection_execution_options` + - event + which is called when :meth:`_engine.Connection.execution_options` + is + called. + + """ + + def engine_disposed(self, engine): + """Intercept when the :meth:`_engine.Engine.dispose` method is called. + + The :meth:`_engine.Engine.dispose` method instructs the engine to + "dispose" of it's connection pool (e.g. :class:`_pool.Pool`), and + replaces it with a new one. Disposing of the old pool has the + effect that existing checked-in connections are closed. The new + pool does not establish any new connections until it is first used. + + This event can be used to indicate that resources related to the + :class:`_engine.Engine` should also be cleaned up, + keeping in mind that the + :class:`_engine.Engine` + can still be used for new requests in which case + it re-acquires connection resources. + + .. versionadded:: 1.0.5 + + """ + + def begin(self, conn): + """Intercept begin() events. + + :param conn: :class:`_engine.Connection` object + + """ + + def rollback(self, conn): + """Intercept rollback() events, as initiated by a + :class:`.Transaction`. + + Note that the :class:`_pool.Pool` also "auto-rolls back" + a DBAPI connection upon checkin, if the ``reset_on_return`` + flag is set to its default value of ``'rollback'``. + To intercept this + rollback, use the :meth:`_events.PoolEvents.reset` hook. + + :param conn: :class:`_engine.Connection` object + + .. seealso:: + + :meth:`_events.PoolEvents.reset` + + """ + + def commit(self, conn): + """Intercept commit() events, as initiated by a + :class:`.Transaction`. + + Note that the :class:`_pool.Pool` may also "auto-commit" + a DBAPI connection upon checkin, if the ``reset_on_return`` + flag is set to the value ``'commit'``. To intercept this + commit, use the :meth:`_events.PoolEvents.reset` hook. + + :param conn: :class:`_engine.Connection` object + """ + + def savepoint(self, conn, name): + """Intercept savepoint() events. + + :param conn: :class:`_engine.Connection` object + :param name: specified name used for the savepoint. + + """ + + def rollback_savepoint(self, conn, name, context): + """Intercept rollback_savepoint() events. + + :param conn: :class:`_engine.Connection` object + :param name: specified name used for the savepoint. + :param context: not used + + """ + # TODO: deprecate "context" + + def release_savepoint(self, conn, name, context): + """Intercept release_savepoint() events. + + :param conn: :class:`_engine.Connection` object + :param name: specified name used for the savepoint. + :param context: not used + + """ + # TODO: deprecate "context" + + def begin_twophase(self, conn, xid): + """Intercept begin_twophase() events. + + :param conn: :class:`_engine.Connection` object + :param xid: two-phase XID identifier + + """ + + def prepare_twophase(self, conn, xid): + """Intercept prepare_twophase() events. + + :param conn: :class:`_engine.Connection` object + :param xid: two-phase XID identifier + """ + + def rollback_twophase(self, conn, xid, is_prepared): + """Intercept rollback_twophase() events. + + :param conn: :class:`_engine.Connection` object + :param xid: two-phase XID identifier + :param is_prepared: boolean, indicates if + :meth:`.TwoPhaseTransaction.prepare` was called. + + """ + + def commit_twophase(self, conn, xid, is_prepared): + """Intercept commit_twophase() events. + + :param conn: :class:`_engine.Connection` object + :param xid: two-phase XID identifier + :param is_prepared: boolean, indicates if + :meth:`.TwoPhaseTransaction.prepare` was called. + + """ + + +class DialectEvents(event.Events): + """event interface for execution-replacement functions. + + These events allow direct instrumentation and replacement + of key dialect functions which interact with the DBAPI. + + .. note:: + + :class:`.DialectEvents` hooks should be considered **semi-public** + and experimental. + These hooks are not for general use and are only for those situations + where intricate re-statement of DBAPI mechanics must be injected onto + an existing dialect. For general-use statement-interception events, + please use the :class:`_events.ConnectionEvents` interface. + + .. seealso:: + + :meth:`_events.ConnectionEvents.before_cursor_execute` + + :meth:`_events.ConnectionEvents.before_execute` + + :meth:`_events.ConnectionEvents.after_cursor_execute` + + :meth:`_events.ConnectionEvents.after_execute` + + + .. versionadded:: 0.9.4 + + """ + + _target_class_doc = "SomeEngine" + _dispatch_target = Dialect + + @classmethod + def _listen(cls, event_key, retval=False): + target = event_key.dispatch_target + + target._has_events = True + event_key.base_listen() + + @classmethod + def _accept_with(cls, target): + if isinstance(target, type): + if issubclass(target, Engine): + return Dialect + elif issubclass(target, Dialect): + return target + elif isinstance(target, Engine): + return target.dialect + elif isinstance(target, Dialect): + return target + elif hasattr(target, "dispatch") and hasattr( + target.dispatch._events, "_no_async_engine_events" + ): + target.dispatch._events._no_async_engine_events() + else: + return None + + def do_connect(self, dialect, conn_rec, cargs, cparams): + """Receive connection arguments before a connection is made. + + This event is useful in that it allows the handler to manipulate the + cargs and/or cparams collections that control how the DBAPI + ``connect()`` function will be called. ``cargs`` will always be a + Python list that can be mutated in-place, and ``cparams`` a Python + dictionary that may also be mutated:: + + e = create_engine("postgresql+psycopg2://user@host/dbname") + + @event.listens_for(e, 'do_connect') + def receive_do_connect(dialect, conn_rec, cargs, cparams): + cparams["password"] = "some_password" + + The event hook may also be used to override the call to ``connect()`` + entirely, by returning a non-``None`` DBAPI connection object:: + + e = create_engine("postgresql+psycopg2://user@host/dbname") + + @event.listens_for(e, 'do_connect') + def receive_do_connect(dialect, conn_rec, cargs, cparams): + return psycopg2.connect(*cargs, **cparams) + + + .. versionadded:: 1.0.3 + + .. seealso:: + + :ref:`custom_dbapi_args` + + """ + + def do_executemany(self, cursor, statement, parameters, context): + """Receive a cursor to have executemany() called. + + Return the value True to halt further events from invoking, + and to indicate that the cursor execution has already taken + place within the event handler. + + """ + + def do_execute_no_params(self, cursor, statement, context): + """Receive a cursor to have execute() with no parameters called. + + Return the value True to halt further events from invoking, + and to indicate that the cursor execution has already taken + place within the event handler. + + """ + + def do_execute(self, cursor, statement, parameters, context): + """Receive a cursor to have execute() called. + + Return the value True to halt further events from invoking, + and to indicate that the cursor execution has already taken + place within the event handler. + + """ + + def do_setinputsizes( + self, inputsizes, cursor, statement, parameters, context + ): + """Receive the setinputsizes dictionary for possible modification. + + This event is emitted in the case where the dialect makes use of the + DBAPI ``cursor.setinputsizes()`` method which passes information about + parameter binding for a particular statement. The given + ``inputsizes`` dictionary will contain :class:`.BindParameter` objects + as keys, linked to DBAPI-specific type objects as values; for + parameters that are not bound, they are added to the dictionary with + ``None`` as the value, which means the parameter will not be included + in the ultimate setinputsizes call. The event may be used to inspect + and/or log the datatypes that are being bound, as well as to modify the + dictionary in place. Parameters can be added, modified, or removed + from this dictionary. Callers will typically want to inspect the + :attr:`.BindParameter.type` attribute of the given bind objects in + order to make decisions about the DBAPI object. + + After the event, the ``inputsizes`` dictionary is converted into + an appropriate datastructure to be passed to ``cursor.setinputsizes``; + either a list for a positional bound parameter execution style, + or a dictionary of string parameter keys to DBAPI type objects for + a named bound parameter execution style. + + The setinputsizes hook overall is only used for dialects which include + the flag ``use_setinputsizes=True``. Dialects which use this + include cx_Oracle, pg8000, asyncpg, and pyodbc dialects. + + .. note:: + + For use with pyodbc, the ``use_setinputsizes`` flag + must be passed to the dialect, e.g.:: + + create_engine("mssql+pyodbc://...", use_setinputsizes=True) + + .. seealso:: + + :ref:`mssql_pyodbc_setinputsizes` + + .. versionadded:: 1.2.9 + + .. seealso:: + + :ref:`cx_oracle_setinputsizes` + + """ + pass |