events.py 文件源码

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:`.ConnectionEvents`.

        :param conn: :class:`.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.

        See also:

        :meth:`.before_execute`

        :meth:`.after_cursor_execute`

        """