Module « sqlalchemy »

Fonction false - module sqlalchemy

Signature de la fonction false

def false() 

Description

false.__doc__

Return a :class:`.False_` construct.

        E.g.::

            >>> from sqlalchemy import false
            >>> print(select(t.c.x).where(false()))
            SELECT x FROM t WHERE false

        A backend which does not support true/false constants will render as
        an expression against 1 or 0::

            >>> print(select(t.c.x).where(false()))
            SELECT x FROM t WHERE 0 = 1

        The :func:`.true` and :func:`.false` constants also feature
        "short circuit" operation within an :func:`.and_` or :func:`.or_`
        conjunction::

            >>> print(select(t.c.x).where(or_(t.c.x > 5, true())))
            SELECT x FROM t WHERE true

            >>> print(select(t.c.x).where(and_(t.c.x > 5, false())))
            SELECT x FROM t WHERE false

        .. versionchanged:: 0.9 :func:`.true` and :func:`.false` feature
           better integrated behavior within conjunctions and on dialects
           that don't support true/false constants.

        .. seealso::

            :func:`.true`