CREATE OR REPLACE VIEW q_day_worker (
   id,
   month,
   worker_id,
   client_hours,
   client_id )
AS
SELECT d.id, TO_CHAR (TRUNC (d.id, 'mm'), 'MON YYYY') MONTH, d.worker_id,
       w.client_hours, w.client_id
  FROM (select q.id, wk.id worker_id from ts_day q, ts_worker wk) d
        left join ts_day_worker w 
        on d.id = w.day_id and d.worker_id = w.worker_id;
/


 -- Triggers for Q_DAY_WORKER 

CREATE OR REPLACE TRIGGER day_worker_iou_tr
INSTEAD OF UPDATE 
ON q_day_worker
REFERENCING NEW AS NEW OLD AS OLD
BEGIN
  -- some code 
 null;
END;
/

CREATE TABLE ts_day
    (id                             DATE NOT NULL);
/

CREATE TABLE ts_worker
    (id                             NUMBER NOT NULL,
    name                           VARCHAR2( 50 ) NOT NULL);
/

CREATE TABLE ts_day_worker
    (day_id                         DATE NOT NULL,
    worker_id                      NUMBER NOT NULL,
    client_hours                  NUMBER,
    client_id                     NUMBER);
/

declare
	id date;
begin
	select day_id
	into id
	from ts_day_worker
	where day_id = :DAY.ID and worker_id = :WORKER_ID
	for update nowait;
exception
	when no_data_found then null;
end;