add update trigger - Maciej

SQL stuff/Maciej_Domanski-EDABA_Lab-3.sql

@@ -1 +1,70 @@
---Maciej Domański 303853 - EDABA Lab 3
+--Maciej Domañski 303853 - EDABA Lab 3
+
+
+-- Show data before triggers
+select * from competition where id < 10
+select * from club where competition_id = 1
+
+-- insert trigger creation
+
+-- update trigger creation
+CREATE OR REPLACE trigger update_trigger after update on competition
+for each row
+begin
+    update club
+    set budget = 2000
+    where 20 < :NEW.prize AND :NEW.id = competition_id;
+end;
+
+-- delete trigger creation
+
+-- Show data that triggers trigger
+
+-- trigger triggers
+update competition
+set prize = 1000
+where id = 1;
+
+-- Show data after trigger
+select * from competition where id < 10
+select * from club where competition_id = 1
+
+
+
+
+-- NEW - valid only for insert/update
+-- OLD - delete/upate 
+--CREATE OR REPLACE trigger update_nb_emp after insert or update or delete on emp
+--for each row
+--begin
+--    -- increase number of employes in given department
+--    update dept
+--    set nb_emp = nb_emp +1 
+--    where deptno = :NEW.deptno;
+--
+--    -- decrease number of employes in given department
+--    -- here we do not decrease number of employees if there are no data in department because of OLD  
+--    update dept
+--    set nb_emp = nb_emp -1 
+--    where deptno = :OLD.deptno;
+--end;
+--
+--
+--select * from dept;
+--select * from emp;
+--insert into emp
+--values(800, 'John', 'Rambo', 7788,'2022-01-20',7000, 0,40);
+--
+--update emp
+--set deptno = 30
+--where empno = 800
+--
+--delete from emp
+--where empno = 800
+--
+--select * from emp
+--
+--update dept
+--set nb_emp = (select count(*) from emp where emp.deptno = dept.deptno)
+--
+