mapper.py 文件源码

def delete_obj(self, objects, uow):
        """called by a UnitOfWork object to delete objects, which involves a
        DELETE statement for each table used by this mapper, for each object in the list."""
        for table in self.tables:
            if not self._has_pks(table):
                continue
            delete = []
            for obj in objects:
                params = {}
                if not hasattr(obj, "_instance_key"):
                    continue
                else:
                    delete.append(params)
                for col in self.pks_by_table[table]:
                    params[col.key] = self._getattrbycolumn(obj, col)
                self.extension.before_delete(self, obj)
            if len(delete):
                clause = sql.and_()
                for col in self.pks_by_table[table]:
                    clause.clauses.append(col == sql.bindparam(col.key))
                statement = table.delete(clause)
                c = statement.execute(*delete)
                if table.engine.supports_sane_rowcount() and c.rowcount != len(delete):
                    raise "ConcurrencyError - updated rowcount %d does not match number of objects updated %d" % (c.cursor.rowcount, len(delete))