def _escape(value):
    if value is None:
        return None
    return str(value).replace("'", "''")

async def model_management_move_down(ns={}):
    """
    下移：与排序上的下一条记录交换 sort_order（已在最后则提示）

    必填参数：
        id (int|str)  模型主键
    """
    model_id = ns.get('id')
    if not model_id:
        return {'status': False, 'msg': 'id is required'}

    db = DBPools()
    async with db.sqlorContext('kboss') as sor:
        try:
            current_sql = """
                SELECT id, sort_order FROM model_management WHERE id = '%s' LIMIT 1;
            """ % _escape(model_id)
            current = await sor.sqlExe(current_sql, {})
            if not current:
                return {'status': False, 'msg': 'model not found'}

            cur = current[0]
            cur_order = int(cur.get('sort_order') or 0)
            cur_id = int(cur.get('id'))

            next_sql = """
                SELECT id, sort_order FROM model_management
                WHERE (sort_order > %s) OR (sort_order = %s AND id > %s)
                ORDER BY sort_order ASC, id ASC
                LIMIT 1;
            """ % (cur_order, cur_order, cur_id)
            next_row = await sor.sqlExe(next_sql, {})
            if not next_row:
                return {'status': True, 'msg': 'already at bottom', 'data': {'sort_order': cur_order}}

            nxt = next_row[0]
            nxt_order = int(nxt.get('sort_order') or 0)
            nxt_id = _escape(nxt.get('id'))

            swap_cur_sql = """
                UPDATE model_management SET sort_order = %s WHERE id = '%s';
            """ % (nxt_order, _escape(model_id))
            swap_nxt_sql = """
                UPDATE model_management SET sort_order = %s WHERE id = '%s';
            """ % (cur_order, nxt_id)
            await sor.sqlExe(swap_cur_sql, {})
            await sor.sqlExe(swap_nxt_sql, {})
            return {
                'status': True,
                'msg': 'move down success',
                'data': {
                    'id': model_id,
                    'sort_order': nxt_order,
                    'swapped_with_id': nxt.get('id'),
                },
            }
        except Exception as e:
            await sor.rollback()
            return {'status': False, 'msg': 'move down failed, %s' % str(e)}

ret = await model_management_move_down(params_kw)
return ret