operations.py 文件源码

def _check_constraint(self, name, source, condition, schema=None, **kw):
        t = sa_schema.Table(source, sa_schema.MetaData(),
                    sa_schema.Column('x', Integer), schema=schema)
        ck = sa_schema.CheckConstraint(condition, name=name, **kw)
        t.append_constraint(ck)
        return ck