DB::fetch_first('SELECT order_id FROM %t WHERE order_body=%s AND total_fee=%d',
     array($this->_table, $order_body, $total_fee));

// 插入数据并返回自增主键
C::t('#aa#aa_t')->insert($data, true);

// 更新数据，其中tid是主键
C::t('#aa#aa_t')->update($tid, $data);

DB::fetch_first('SELECT order_id FROM %t WHERE order_body=%s AND total_fee=%d',
     array($this->_table, $order_body, $total_fee));

// 插入数据并返回自增主键
C::t('#aa#aa_t')->insert($data, true);

// 更新数据，其中tid是主键
C::t('#aa#aa_t')->update($tid, $data);