Question

Here I have the following trigger:

USE dbsspf;

DELIMITER $$

CREATE
DEFINER = 'root'@'localhost'
TRIGGER TR_ASSIGN_PAGEINDEX
AFTER INSERT
ON LIB_RECORDS
FOR EACH ROW
BEGIN

  UPDATE LIB_RECORDS
  SET
  PAGE_INDEX = 13;


END
$$

DELIMITER ;

As you can see I’m just updating the table in my trigger. However when I insert a new record the trigger does not fire. Can you please show me what I’ve missed?

Answer 1

B.5.9: Can triggers access tables?

A trigger can access both old and new data in its own table. A trigger
can also affect other tables, but it is not permitted to modify a
table that is already being used (for reading or writing) by the
statement that invoked the function or trigger.

http://dev.mysql.com/doc/refman/5.5/en/faqs-triggers.html#qandaitem-B-5-1-9

In other words, a trigger on LIB_RECORDS cannot write other rows on LIB_RECORDS.