schemaobj.py 文件源码

def _ensure_table_for_fk(self, metadata, fk):
        """create a placeholder Table object for the referent of a
        ForeignKey.

        """
        if isinstance(fk._colspec, string_types):
            table_key, cname = fk._colspec.rsplit('.', 1)
            sname, tname = self._parse_table_key(table_key)
            if table_key not in metadata.tables:
                rel_t = sa_schema.Table(tname, metadata, schema=sname)
            else:
                rel_t = metadata.tables[table_key]
            if cname not in rel_t.c:
                rel_t.append_column(sa_schema.Column(cname, NULLTYPE))