operations.py 文件源码

def _unique_constraint(self, name, source, local_cols, schema=None, **kw):
        t = sa_schema.Table(source, sa_schema.MetaData(),
                    *[sa_schema.Column(n, NULLTYPE) for n in local_cols],
                    schema=schema)
        kw['name'] = name
        uq = sa_schema.UniqueConstraint(*[t.c[n] for n in local_cols], **kw)
        # TODO: need event tests to ensure the event
        # is fired off here
        t.append_constraint(uq)
        return uq