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Oracle Triggers


/*ADDING NEW ROW BY TRIGGER 
/*ORACLE 9i SCOTT/TIGER 
/* TRIGGERED ON EMP TABLE
/*CREATING NEW TABLE WHICH WILL UPDATED BY TRIGGERED */

 CREATE TABLE DEPT_SUMMARY
(
DEPTNO NUMBER,
AVG_SALARY NUMBER,
NO_OF_EMP NUMBER
);

 create or replace
TRIGGER TG_EMP_SAL_SUMMARY
AFTER INSERT OR DELETE OR UPDATE ON EMP
DECLARE
  CURSOR CUR_EMP
  IS
    SELECT COUNT(ENAME),SUM(SAL),DEPTNO FROM EMP GROUP BY DEPTNO;
    V_CNT NUMBER;
    V_SAL EMP.SAL%TYPE:=0;
    V_DEPT EMP.DEPTNO%TYPE:=0;
BEGIN
  DELETE DEPT_SUMMARY;
  OPEN CUR_EMP;
    LOOP
      FETCH CUR_EMP INTO V_CNT,V_SAL,V_DEPT;
      EXIT WHEN NOT CUR_EMP%FOUND;
      INSERT INTO DEPT_SUMMARY
      VALUES(V_DEPT,V_SAL/V_CNT,V_CNT);
    END LOOP;
END TG_EMP_SAL_SUMMARY;

 /*INSERTING NEW ROW INTO EMP*/
INSERT INTO EMP
VALUES(100,'DIBYENDU','ADMIN',15,'12-JAN-00',6580,250,20);

 /*OUTPUT ON DEPT_SUMMARY TABLE
DEPTNO AVG_SALARY NO_OF_EMP
10 2916.66667 3
20 3204.375 8
30 1560 5 


BASED ON (EMP TABLE)
ENAME SAL DEPTNO
SMITH 800 20
ALLEN 1600 20
WARD 1250 30
JONES 2975 20
MARTIN 1250 30
BLAKE 2850 30
CLARK 2450 10
SCOTT 3000 20
KING 5000 10
TURNER 1500 30
ADAMS 1100 20
JAMES 950 30
FORD 3000 20
MILLER 1300 10
ENAME SAL DEPTNO
DIBYENDU 6580 20
DIBYENDU 6580 20


*/
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