第五阶段
Q.编写一个数据包，它有两个函数和两个过程以操作“emp”表。
该数据包要执行的任务为：
插入一个新雇员；删除一个现有雇员；显示指定雇员的整体薪水（薪水+佣金）；显示指定雇员所在部门名称。
A.
CREATE OR REPLACE PACKAGE emppack AS
PROCEDURE insrec(pempno emp.empno%TYPE,pename emp.ename%TYPE,
pjob emp.job%TYPE,pmgr emp.mgr%TYPE,
phiredate emp.hiredate%TYPE,psal emp.sal%TYPE,
pcomm emp.comm%TYPE,pdeptno emp.deptno%TYPE);
PROCEDURE delrec(pempno IN NUMBER);
FUNCTION selsal(pempno NUMBER) RETURN NUMBER;
FUNCTION seldname(pempno NUMBER) RETURN VARCHAR2;
END;
/
CREATE OR REPLACE PACKAGE BODY emppack AS
PROCEDURE insrec(pempno emp.empno%TYPE,pename emp.ename%TYPE,
pjob emp.job%TYPE,pmgr emp.mgr%TYPE,
phiredate emp.hiredate%TYPE,psal emp.sal%TYPE,
pcomm emp.comm%TYPE,pdeptno emp.deptno%TYPE)
IS
BEGIN
INSERT INTO emp VALUES(pempno,pename,pjob,pmgr,phiredate,
psal,pcomm,pdeptno);
DBMS_OUTPUT.PUT_LINE('1 record is created.');
END insrec;
PROCEDURE delrec(pempno IN NUMBER)
IS
BEGIN
DELETE FROM emp WHERE empno=pempno;
DBMS_OUTPUT.PUT_LINE('1 record is deleted.');
END delrec;
FUNCTION selsal(pempno NUMBER) RETURN NUMBER
IS
vTotalSal NUMBER;
BEGIN
SELECT NVL(sal,0)+NVL(comm,0) INTO vTotalSal
FROM emp
WHERE empno=pempno;
RETURN vTotalSal;
END selsal;
FUNCTION seldname(pempno NUMBER) RETURN VARCHAR2
IS
vdname dept.dname%TYPE;
BEGIN
SELECT dname INTO vdname
FROM emp,dept
WHERE empno=pempno AND emp.deptno=dept.deptno;
RETURN vdname;
END seldname;
END;
/
--执行包中的过程和函数
EXECUTE emppack.insrec(1111,'Goldens','MANAGER',7698,'2003-01-18',2000,400,30);
EXECUTE emppack.delrec(1111);
DECLARE
salary NUMBER;
BEGIN
salary:=emppack.selsal(7369);
DBMS_OUTPUT.PUT_LINE('Total Salary is '||salary);
END;
/
DECLARE
department VARCHAR2(30);
BEGIN
department:=emppack.seldname(7369);
DBMS_OUTPUT.PUT_LINE('Department name is '||department);
END;
/
Q.编写一个数据库触发器以显示当任何时候雇员加薪时的加薪情况。
A.
CREATE OR REPLACE TRIGGER emp_SalUp
AFTER UPDATE OF sal ON emp
FOR EACH ROW
DECLARE
vsal NUMBER;
BEGIN
vsal:=NVL(:NEW.sal,0)-NVL(:OLD.sal,0);
IF vsal<=0 THEN
RAISE_APPLICATION_ERROR(-20001,'Increased Salary is not zero and littler than zero');
END IF;
END;
/
Q.编写一个数据库触发器，它允许用户只在上午9.00到下午5.00之间执行DML任务。
A.
CREATE OR REPLACE TRIGGER operate_time_limited
BEFORE INSERT OR UPDATE OR DELETE ON emp
--FOR EACH ROW
DECLARE
vtime NUMBER;
BEGIN
vtime:=TO_NUMBER(TO_CHAR(SYSDATE,'HH24'));
IF vtime NOT BETWEEN 9 AND 17 THEN
RAISE_APPLICATION_ERROR(-20444,'Sorry!Not Except 9AM and 5PM.');
END IF;
END;
/
Q.编写一个数据为触发器以检查某个组织中不能有两个总裁。
A.
CREATE OR REPLACE TRIGGER check_president
BEFORE INSERT OR UPDATE ON emp
FOR EACH ROW
WHEN (UPPER(NEW.job)='PRESIDENT')
DECLARE
vCount NUMBER;
BEGIN
SELECT COUNT(job) INTO vCount
FROM emp
WHERE UPPER(job)='PRESIDENT'; --把总统的个数统计出来，当为0时，变量值为0
IF vCount>0 THEN
RAISE_APPLICATION_ERROR(-20444,'Sorry!Can''t have two President.');
END IF;
END;
/
Q.编写一个数据库触发器，当任何时候某个部门从”dept”中删除时，该触发器将从”emp”表中删除该部门的所有雇员。
A.
CREATE OR REPLACE TRIGGER del_emp_deptno
BEFORE DELETE ON dept
FOR EACH ROW
BEGIN
DELETE FROM emp WHERE deptno=:OLD.deptno;
END;
/
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