Använder datum i en kontrollbegränsning, Oracle

En kontrollbegränsning kan tyvärr inte referera till en funktion som SYSDATE. Du skulle behöva skapa en utlösare som kontrollerade dessa värden när DML inträffar, dvs.

CREATE OR REPLACE TRIGGER trg_check_dates
  BEFORE INSERT OR UPDATE ON table1
  FOR EACH ROW
BEGIN
  IF( :new.CloseDate <= SYSDATE )
  THEN
    RAISE_APPLICATION_ERROR( -20001, 
          'Invalid CloseDate: CloseDate must be greater than the current date - value = ' || 
          to_char( :new.CloseDate, 'YYYY-MM-DD HH24:MI:SS' ) );
  END IF;
  IF( :new.CloseDate > add_months(SYSDATE,12) )
  THEN
    RAISE_APPLICATION_ERROR( -20002, 
         'Invalid CloseDate: CloseDate must be within the next year - value = ' || 
         to_char( :new.CloseDate, 'YYYY-MM-DD HH24:MI:SS' ) );
  END IF;
  IF( :new.StartDate <= add_months(:new.CloseDate,24) )
  THEN
    RAISE_APPLICATION_ERROR( -20002, 
          'Invalid StartDate: StartDate must be within 24 months of the CloseDate - StartDate = ' || 
          to_char( :new.StartDate, 'YYYY-MM-DD HH24:MI:SS' ) ||
          ' CloseDate = ' || to_char( :new.CloseDate , 'YYYY-MM-DD HH24:MI:SS' ) );
  END IF;
END;