Class conv

lib/sqlalchemy/sql/elements.py:5474–5522

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:

class conv(_truncated_label):
    """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"``

    .. seealso::

        :ref:`constraint_naming_conventions`

    """

    __slots__ = ()


# for backwards compatibility in case