Re: create trigger statement

[davy timmermans]

one trigger with 3 statements (insert, delete , update) inside the trigger
important to know: this statements are performed on a SHADOWTABLE.

the delete trigger should check for each device from table DEVICE if it has a record in the SHADOWTABLE on deleting from table A

4 possibilities when checking SHADOWTABLE :

no entry
entry with action 'U','I' ,'D' specified


pseudo code

AFTER DELETE on A

//it should check for each device wich statement to perform!!!::

foreach DEVICE ID from DEVICE {

INSERT INTO SHADOWTABLE ///this means that there was no entry for old.A
VALUES (old.A, DEVICE ID, ‘D’)
WHERE action != ‘I’ or ’U’ ; //

ELSE

DELETE FROM SHADOWTABLE
WHERE action= ‘I’ ;

ELSE

UPDATE SHADOWTABLE
SET action=‘D’ where action=’U’

}

clear?? otherwise ask me ;) now I'm busy with examinations;)