sqlalchemy.sql.elements.conv

Mark a string indicating that a name has already been converted by a naming convention. This is a string subclass that indicates a name that should not be subject to any further naming conventions. E.g. when we create a :class:`.Constraint` using a naming convention as follows:: m = MetaData(naming_convention={ "ck": "ck_%(table_name)s_%(constraint_name)s" }) t = Table('t', m, Column('x', Integer), CheckConstraint('x > 5', name='x5')) The name of the above constraint will be rendered as ``"ck_t_x5"``. That is, the existing name ``x5`` is used in the naming convention as the ``constraint_name`` token. In some situations, such as in migration scripts, we may be rendering the above :class:`.CheckConstraint` with a name that's already been converted. In order to make sure the name isn't double-modified, the new name is applied using the :func:`_schema.conv` marker. We can use this explicitly as follows:: m = MetaData(naming_convention={ "ck": "ck_%(table_name)s_%(constraint_name)s" }) t = Table('t', m, Column('x', Integer), CheckConstraint('x > 5', name=conv('ck_t_x5'))) Where above, the :func:`_schema.conv` marker indicates that the constraint name here is final, and the name will render as ``"ck_t_x5"`` and not ``"ck_t_ck_t_x5"`` .. versionadded:: 0.9.4 .. seealso:: :ref:`constraint_naming_conventions`