如何从Sql过程发送消息错误? [英] How I can send a Message Error From My Sql Procedure?

问题描述

大家好，

我正在使用sql进行事务处理，但是我想发送一条消息错误
如果在插入之前该寄存器已经存在.

例如:

Hello Everyone,

I am making a transaction procedure in my sql, but I want to send a message-error
If the register already exists before I insert.

For example:

CREATE DEFINER=`root`@`localhost` PROCEDURE `AsigPolizClau` //.......--->more code
  BEGIN
  
  START TRANSACTION;
  
    IF((SELECT id FROM poliza where field1=fk_field1) IS NULL) THEN    
      BEGIN
        /*
          ...
          ...
        */
      END;
   ELSE
      BEGIN
       //HERE I WANT TO SEND A MESSAGE ERROR!!!!!!!! (HOW????????)
       //HERE I WANT TO SEND A MESSAGE ERROR!!!!!!!! (HOW????????)
       //HERE I WANT TO SEND A MESSAGE ERROR!!!!!!!! (HOW????????)
      END;
   END IF;

   SET a=(SELECT @@error_count);
   IF a > 0 THEN
    ROLLBACK;
   ELSE
    COMMIT;
   END IF;   


  END

我希望该过程完成，并向我的
发送一条消息错误 C#中的MySqlCommand变量.
然后从C#代码中给出一条消息，也许是一条从sql过程粘贴到
的消息 C#中的过程.

这是可能的吗?

在此先感谢!!

I want that the procedure finished and send a message error to my
MySqlCommand variable in C#.
and I give a message from my C# code, maybe a message pased from sql procedure to
the procedure in c#.

It is posible???

Thanks in advance!!

推荐答案

SqlDataReader dr = cmd.ExecuteReader(); 
dr.Read().ToString(); <-- error is returned here

据我所知，没有直接的机制.例如，一种解决方法是您:
-从存储过程返回信息是否成功(例如0/1)
-在此过程中，将有关错误的描述行添加到自定义错误表中
-在调用应用程序中，如果收到0，则会从错误表中读取消息

As far as I know there''s no direct mechanism. One workaround is for example that you:
- return information from the stored procedure if it succeeds or not (like 0/1)
- in the procedure you add descriptive rows about the error to a custom error table
- in the calling application if you receive 0 you read the messages from the error table

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