Trigger

CREATE OR REPLACE TRIGGER TRG_GRIESMAYER_ACCOUNTS
BEFORE INSERT or UPDATE on ACCOUNT
FOR EACH ROW
BEGIN
  IF (:new.BALANCE < :new.CREDIT_LIMIT) THEN
    raise_application_error (-20999, 'The balance ' || :new.BALANCE || ' is under the credit limit' || :new.CREDIT_LIMIT || '!');
  END IF;
END;

INSERT INTO ACCOUNT VALUES (3006, 'Max', -4000, -2000);

  IF (INSERTING) THEN
    SELECT SEQ_ACCOUNT_ID.nextval INTO :new.ACCOUNT_ID
    FROM   DUAL;

    IF ((:new.CREDIT_LIMIT is NULL) or (:new.CREDIT_LIMIT > 0)) THEN
      SELECT -1000 INTO :new.CREDIT_LIMIT
      FROM   DUAL;
    END IF;
  END IF;