Before Insert Trigger - Capture In Value to Compare to Value in Existing Table

Before inserting a row in a table I would like to check the value of a particular field in the new candidate row against the existence of the value in a field in another table.

How do I "grab" the new value?

Example:

CREATE OR REPLACE TRIGGER check_zip_trig BEFORE INSERT
ON address
REFERENCING NEW AS New OLD AS Old
FOR EACH ROW    IF NOT EXISTS(SELECT ZIPCODE FROM ZIP WHERE ZIPCODE = NEW:ZIP;) THEN
       RAISE_APPLICATION_ERROR (- 20212, 'Cannot perform insert. Invalid ZIP Code');

   END IF; END ; Received on Sat Mar 10 2007 - 15:01:52 CST