<"'.$data['order_id'].'","'.$data['goods_id'].'","'.$data['uid'].'","'.$data['addtime'].'")';   
    $result = $pdo->exec($sql);
    if(!$result){
     $pdo->rollBack();
     $this->_error = '订单创建失败';
     return false;
    }
    $pdo->commit();//提交
    $this->_error = '购买成功';
    return true;

   }else{
    $this->_error = '库存不足';
    return false;
   }
  }catch(PDOException $e){
   echo $e->getMessage();
   $pdo->rollBack();
  }


 }
 /*
  * 创建订单
  * mysql 事物处理，也可以用存储过程
  *
 */
 private function create_order($goodsInfo){
  //生成订单
  $data    = [];
  $data['order_id'] = $this->_orderModel->buildOrderNo();
  $data['goods_id'] = $goodsInfo['id'];
  $data['addtime'] = time();
  $data['uid']  = 1;
  $order_rs = $this->_orderModel->create_order($data);

  //库存减少
  $gid = $goodsInfo['id'];
  $sql = 'UPDATE goods SET counts = counts - 1 WHERE id = '.$gid;
  $result = $this->_goodsModel->exect($sql);
  return true;
 }
}