-- Init CREATE VIEW seattle_employees_v AS SELECT FROM employees depar

-- Init
CREATE VIEW seattle_employees_v AS SELECT e.* FROM employees e, departments d, locations l, countries c WHERE e.department_id=d.department_id AND l.location_id=d.location_id AND l.country_id=c.country_id AND c.country_name='United States of America' AND l.city='Seattle';

CREATE TABLE seattle_employees AS
SELECT * from seattle_employees_v;

ALTER TABLE seattle_employees 
ADD PRIMARY KEY(employee_id);

CREATE INDEX se_salary ON seattle_employees
(salary);

CREATE INDEX se_last_name ON seattle_employees
(last_name);


CREATE TABLE seattle_employees_log ( employee_id int );
ALTER TABLE seattle_employees_log 
ADD PRIMARY KEY(employee_id);

-- refresh_seattle_employees
CREATE OR REPLACE FUNCTION refresh_seattle_employees (id INTEGER) RETURNS
VOID SECURITY DEFINER
AS $$
	DELETE FROM seattle_employees WHERE employee_id=$1;
	INSERT INTO seattle_employees SELECT * FROM seattle_employees_v WHERE employee_id=$1;
$$ LANGUAGE SQL;


-- Method
CREATE OR REPLACE  synchronizeSeattleView() RETURNS VOID AS $$
DECLARE
	emp RECORD;
BEGIN

	-- Get ids from log
	FOR emp IN (select employee_id from seattle_employees_log) LOOP
	
		PERFORM refresh_seattle_employees(emp.employee_id);

	END LOOP;
	
	-- Clear log
	TRUNCATE TABLE seattle_employees_log;
END;
$$ LANGUAGE PLPGSQL;


-- Insert Trigger
CREATE OR REPLACE FUNCTION mv_se_ins ()
RETURNS TRIGGER
AS $$
begin
	insert into seattle_employees_log values(new.employee_id);
	RETURN null;
end;
$$ LANGUAGE PLPGSQL;

CREATE TRIGGER mv_se_employees_ins AFTER
INSERT ON employees FOR EACH ROW EXECUTE
PROCEDURE mv_se_ins();

-- Update Trigger
CREATE OR REPLACE FUNCTION mv_se_upd ()
RETURNS TRIGGER
AS $$
begin
	if old.employee_id=new.employee_id then
		insert into seattle_employees_log values(new.employee_id);	
	else
		insert into seattle_employees_log values(old.employee_id);
		insert into seattle_employees_log values(new.employee_id);
	end if;
	RETURN null;
end;
$$ LANGUAGE PLPGSQL;

CREATE TRIGGER mv_se_employees_upd AFTER
UPDATE ON employees FOR EACH ROW EXECUTE
PROCEDURE mv_se_upd();

-- Delete Trigger
CREATE OR REPLACE FUNCTION mv_se_del ()
RETURNS TRIGGER
AS $$
begin
	insert into seattle_employees_log values(old.employee_id);
	RETURN null;
end;
$$ LANGUAGE PLPGSQL;

CREATE TRIGGER mv_se_employees_del AFTER
DELETE ON employees FOR EACH ROW EXECUTE
PROCEDURE mv_se_del();