mysql.py 文件源码

def visit_column(self, delta):
        table = delta.table
        colspec = self.get_column_specification(delta.result_column)
        if delta.result_column.autoincrement:
            primary_keys = [c for c in table.primary_key.columns
                       if (c.autoincrement and
                            isinstance(c.type, sqltypes.Integer) and
                            not c.foreign_keys)]

            if primary_keys:
                first = primary_keys.pop(0)
                if first.name == delta.current_name:
                    colspec += " AUTO_INCREMENT"
        q = util.safe_quote(table)
        old_col_name = self.preparer.quote(delta.current_name, q)

        self.start_alter_table(table)

        self.append("CHANGE COLUMN %s " % old_col_name)
        self.append(colspec)
        self.execute()