Classe « Query »

Méthode sqlalchemy.orm.Query.update

Signature de la méthode update

def update(self, values, synchronize_session='evaluate', update_args=None) 

Description

update.__doc__

Perform an UPDATE with an arbitrary WHERE clause.

        Updates rows matched by this query in the database.

        E.g.::

            sess.query(User).filter(User.age == 25).\
                update({User.age: User.age - 10}, synchronize_session=False)

            sess.query(User).filter(User.age == 25).\
                update({"age": User.age - 10}, synchronize_session='evaluate')

        .. warning::

            See the section :ref:`orm_expression_update_delete` for important
            caveats and warnings, including limitations when using arbitrary
            UPDATE and DELETE with mapper inheritance configurations.

        :param values: a dictionary with attributes names, or alternatively
         mapped attributes or SQL expressions, as keys, and literal
         values or sql expressions as values.   If :ref:`parameter-ordered
         mode <updates_order_parameters>` is desired, the values can be
         passed as a list of 2-tuples;
         this requires that the
         :paramref:`~sqlalchemy.sql.expression.update.preserve_parameter_order`
         flag is passed to the :paramref:`.Query.update.update_args` dictionary
         as well.

        :param synchronize_session: chooses the strategy to update the
         attributes on objects in the session.   See the section
         :ref:`orm_expression_update_delete` for a discussion of these
         strategies.

        :param update_args: Optional dictionary, if present will be passed
         to the underlying :func:`_expression.update`
         construct as the ``**kw`` for
         the object.  May be used to pass dialect-specific arguments such
         as ``mysql_limit``, as well as other special arguments such as
         :paramref:`~sqlalchemy.sql.expression.update.preserve_parameter_order`.

        :return: the count of rows matched as returned by the database's
         "row count" feature.


        .. seealso::

            :ref:`orm_expression_update_delete`