operations.py 文件源码

def _foreign_key_constraint(self, name, source, referent,
                                    local_cols, remote_cols,
                                    onupdate=None, ondelete=None,
                                    deferrable=None, source_schema=None,
                                    referent_schema=None):
        m = sa_schema.MetaData()
        if source == referent:
            t1_cols = local_cols + remote_cols
        else:
            t1_cols = local_cols
            sa_schema.Table(referent, m,
                    *[sa_schema.Column(n, NULLTYPE) for n in remote_cols],
                    schema=referent_schema)

        t1 = sa_schema.Table(source, m,
                *[sa_schema.Column(n, NULLTYPE) for n in t1_cols],
                schema=source_schema)

        tname = "%s.%s" % (referent_schema, referent) if referent_schema \
                else referent
        f = sa_schema.ForeignKeyConstraint(local_cols,
                                            ["%s.%s" % (tname, n)
                                            for n in remote_cols],
                                            name=name,
                                            onupdate=onupdate,
                                            ondelete=ondelete,
                                            deferrable=deferrable
                                            )
        t1.append_constraint(f)

        return f