FOR EACH ROW triggered actions

A FOR EACH ROW triggered action executes once for each row that the triggering statement affects. For example, if the triggering statement has the following syntax, a FOR EACH ROW triggered action executes once for each row in the items table in which the manu_code column has a value of ‘KAR':

UPDATE items SET quantity = quantity * 2 
   WHERE manu_code = 'KAR';

If the triggering event does not process any rows, a FOR EACH ROW triggered action does not execute.

For a trigger on a table, if the triggering event is a SELECT statement, the trigger is a called a Select trigger, and the triggered actions execute after all processing on the retrieved row is complete. The triggered actions might not execute immediately; however, because a FOR EACH ROW action executes for every instance of a row that the query returns. For example, in a SELECT statement with an ORDER BY clause, all rows must be qualified against the WHERE clause before they are sorted and returned.