FORBIDE DELETE

[Inna M.]

I looked in the forum about this subject, and there is unfortunetely no concrete answer :(

I have 2 tables: Attributes and IntegerValues. Both of them have an attribute "Value_Id".

Problem: i need to forbide deleting row from tha table IntegerValues if the Value_Id is used in the table Attributes. If it's used in the table Attributes - Trigger has to forbide delete and give back an error message(or something...(?)).

My Trigger is:

CREATE TRIGGER bd BEFORE DELETE on IntegerValues
BEGIN
BEGIN TRANSACTION;

DECLARE val_id int;
select Value_Id into val_id
from Attributes
where Value_Id = old.Value_Id;
if ( attr_Val <> 0 ) then
ROLLBACK;
end if;

END TRANSACTION;
END;