MySQL triggers cannot update rows in same table the trigger is assigned to. Suggested workaround?

Question

MySQL doesn\'t currently support updating rows in the same table the trigger is assigned to since the call could become recursive. Does anyone have suggestions on a good wor

Answer 1

You can actually up the rows in the same table as the trigger. The thread you linked to even has the solution.

For example:

TestTable ( id / lastmodified / random )

create trigger insert_lastmod
before insert on TestTable
for each row
set NEW.lastmodified = NOW();

insert into TestTable ( `random` ) values ( 'Random' );

select * from TestTable;
+----+---------------------+---------------------+
| id | lastmodified        | random              |
+----+---------------------+---------------------+
|  1 | 2010-12-22 14:15:23 | Random              |
+----+---------------------+---------------------+

Answer 2

This worked for me :D

On Before / Update.

BEGIN
 SET NEW.DateTimeUpdated = NOW();
END

Answer 3

I suppose you could call the stored proc in your trigger. HOwever, if you want to update some fields in the same records that you are changing (such as an updatedby or lastupdated column) then you can do this in a beofre trigger according to the refernce manual. http://dev.mysql.com/doc/refman/5.0/en/trigger-syntax.html

This is a common operation for triggers and I find it difficult to believe it isn't supported.

Answer 4

You can actually do that The below is an example for same

DELIMITER $$
create trigger test2 
before insert on ptrt 
for each row 
begin 
if NEW.DType = "A" then 
set NEW.PA = 500; 

elseif NEW.DType = "B" then 
set NEW.PA = 1000; 

else 
set NEW.PA = 0; 
END IF; 
END;$$

DELIMITER;

Answer 5

If you want to update column that you don't read in trigger function, then as a workaround, you could put that column into separate table.