ASA SQL Reference
SQL Language Elements
Search conditions
Trigger operation conditions

Example

CREATE TRIGGER tr BEFORE INSERT, UPDATE, DELETE
ON sample_table
REFERENCING OLD AS t1old
FOR EACH ROW
BEGIN
DECLARE msg varchar(255);
SET msg = 'This trigger was fired by an ';
IF INSERTING THEN
SET msg = msg || 'insert'
ELSEIF DELETING THEN
set msg = msg || 'delete'
ELSEIF UPDATING THEN
set msg = msg || 'update'
END IF;
MESSAGE msg TO CLIENT
END