从存储过程处理程序中访问错误堆栈

Question

I have stored procedure that calls another stored procedure. Let's call them OUTER and INNER.

The INNER procedure can detect errors in the input and if it does it will raise/signal it like this

signal sqlstate '45000' set message_text = 'some error';

In OUTER procedure I'm able to catch this with a normal handler like this

declare exit handler for sqlstate '45000'
begin
  -- this is where I'd like to access the message_text from INNER
end    

but I fail to find a way of reading the internal parts of the signal.

I've seen that it might be available in 5.6 but that isn't GA yet and will probably be shaky for a while after release.

Any takers on this.?

Answer 1

When a SQL condition (warning, error) is raised and then caught in an exception handler, the only way to know details about what happened is to use the GET DIAGNOSTICS statement.

See the doc: http://dev.mysql.com/doc/refman/5.6/en/get-diagnostics.html

This statement is indeed only available starting with 5.6.

For 5.5 and earlier, there is no way to get access -- that is, from code in an exception handler -- to the data you are looking for.

Answer 2

As this is not available until 5.6 I ended up creating a stored procedure that both sends the signal but also sets the error text in a session varible

delimiter //

create procedure send_signal (error_text varchar(255))
begin
  set @session_error_text := error_text;
  signal sqlstate '45000' set message_text = error_text;
end//

delimiter ;