华南农业大学数据库系统概念实验报告七.doc

数据库系统实验报告七学号姓名实验时间2014-12-31实验名称触发器实验学时2准备材料1. SQL Plus命令手册2. PL/SQL用户手册3. 实验教材中实验七扩展实验1.完成触发器的定义、执行与管理操作 (此部分内容不要求在实验室完成，不用写入实验报告。)实验环境Oracle 9i(及以上版本)服务器SQL Plus/ SQL Plus work sheet客户端实验目的1 熟悉PL/SQL语法2. 利用PL/SQL编程访问数据库实验内容及步骤1. 完成实验指导书实验七所有实验内容【训练1】CREATE TABLE logs(LOG_ID NUMBER(10) PRIMARY KEY,LOG_TABLE VARCHAR2(10) NOT NULL,LOG_DML VARCHAR2(10),LOG_KEY_ID NUMBER(10),LOG_DATE DATE,LOG_USER VARCHAR2(15);CREATE SEQUENCE logs_id_squ INCREMENT BY 1 START WITH 1 MAXVALUE 9999999 NOCYCLE NOCACHE;CREATE OR REPLACE TRIGGER DML_LOGBEFORE -触发时间为操作前DELETE OR INSERT OR UPDATE - 由三种事件触发ON empFOR EACH ROW - 行级触发器BEGINIF INSERTING THEN INSERT INTO logs VALUES(logs_id_squ.NEXTVAL,EMP,INSERT,:new.empno,SYSDATE,USER); ELSIF DELETING THEN INSERT INTO logs VALUES(logs_id_squ.NEXTVAL,EMP,DELETE,:old.empno,SYSDATE,USER); ELSE INSERT INTO logs VALUES(logs_id_squ.NEXTVAL,EMP,UPDATE,:new.empno,SYSDATE,USER); END IF;END;INSERT INTO emp(empno,ename,job,sal) VALUES(8001,MARY,CLERK,1000);COMMIT;SELECT * FROM LOGS;【练习1】修改、删除刚刚插入的雇员记录，提交后检查LOGS表的结果。update emp set sal = sal*5where ename = MARY;COMMIT;DELETE FROM emp WHERE empno = 8001;COMMIT;SELECT * FROM LOGS;【练习2】为DEPT表创建同样的触发器，使用LOGS表进行记录，并检验结果。CREATE OR REPLACE TRIGGER DEPT_LOGBEFORE -触发时间为操作前DELETE OR INSERT OR UPDATE - 由三种事件触发ON deptFOR EACH ROW - 行级触发器BEGINIF INSERTING THEN INSERT INTO logs VALUES(logs_id_squ.NEXTVAL,DEPT,INSERT,:new.deptno,SYSDATE,USER); ELSIF DELETING THEN INSERT INTO logs VALUES(logs_id_squ.NEXTVAL,DEPT,DELETE,:old.deptno,SYSDATE,USER); ELSE INSERT INTO logs VALUES(logs_id_squ.NEXTVAL,DEPT,UPDATE,:new.deptno,SYSDATE,USER); END IF;END;INSERT INTO dept(deptno,dname,loc) VALUES(50,JIAN,GUANGZHOU);COMMIT;SELECT * FROM LOGS;【训练2】CREATE TABLE logerr(NUM NUMBER(10) NOT NULL,MESSAGE VARCHAR2(50) NOT NULL);CREATE OR REPLACE TRIGGER log_salBEFOREUPDATE OF salON empFOR EACH ROWWHEN (new.job=CLERK AND (ABS(new.sal-old.sal)>200) DECLARE v_no NUMBER;BEGIN SELECT COUNT(*) INTO v_no FROM logerr; INSERT INTO logerr VALUES(v_no+1,雇员|:new.ename|的原工资：|:old.sal|新工资：|:new.sal);END;UPDATE emp SET sal=sal+550 WHERE empno=7788;UPDATE emp SET sal=sal+500 WHERE empno=7369;UPDATE emp SET sal=sal+50 WHERE empno=7876;COMMIT;SELECT * FROM logerr;【训练3】CREATE OR REPLACE TRIGGER CHECK_SALBEFOREUPDATEON empFOR EACH ROWBEGINIF :new.job=CLERK AND (:new.sal<500 OR :new.sal>2000) THEN RAISE_APPLICATION_ERROR(-20001, 工资修改超出范围,操作取消！); END IF;END;UPDATE emp SET sal=800 WHERE empno=7876;UPDATE emp SET sal=450 WHERE empno=7876;COMMIT;SELECT empno,ename,job,sal FROM emp WHERE empno=7876;【练习3】限定对emp表的修改，只能修改部门10的雇员工资。CREATE OR REPLACE TRIGGER CHECK_NOBEFOREUPDATEON empFOR EACH ROWBEGINIF :new.DEPTNO<>10 THEN RAISE_APPLICATION_ERROR(-20001, 修改的部门不符,操作取消！); END IF;END;UPDATE emp SET sal=8000 WHERE deptno=20;UPDATE emp SET sal=6789 WHERE deptno=30;UPDATE emp SET sal=888 WHERE deptno=10;select * from emp;【训练4】CREATE TRIGGER CASCADE_UPDATEAFTER UPDATE OF deptnoON DEPTFOR EACH ROWBEGINUPDATE EMP SET EMP.DEPTNO=:NEW.DEPTNOWHERE EMP.DEPTNO=:OLD.DEPTNO;END;UPDATE dept SET deptno=11 WHERE deptno=10;COMMIT;SELECT empno,ename,deptno FROM emp;【练习4】建立级联删除触发器CASCADE_DELETE，当删除部门时，级联删除EMP表的雇员记录。CREATE TRIGGER CASCADE_DELETEAFTER DELETE ON DEPT FOR EACH ROWBEGINDELETE FROM EMP WHERE EMP.DEPTNO=:OLD.DEPTNO;END;DELETE FROM DEPT WHERE DEPTNO = 11;COMMIT;SELECT * FROM EMP;SELECT * FROM DEPT;【训练5】CREATE OR REPLACE TRIGGER INITCAPBEFORE INSERT ON EMPFOR EACH ROWBEGIN :new.ename:=INITCAP(:new.ename);END;INSERT INTO emp(empno,ename,job,sal) VALUES(1000,BILL,CLERK,1500);SELECT ename,job,sal FROM emp WHERE empno=1000;【练习5】限定一次对雇员的工资修改不超过原工资的10%。CREATE OR REPLACE TRIGGER CHECK_SALARYBEFOREUPDATE OF SAL ON EMPFOR EACH ROWBEGIN IF :new.SAL >= :old.SAL*1.1 THEN :new.SAL:= :old.SAL; ELSIF :new.SAL <= :old.SAL*0.9 THEN :new.SAL:= :old.SAL; END IF;END;SELECT * FROM EMP WHERE EMPNO = 7876;UPDATE EMP SET SAL = SAL*1.08 WHERE EMPNO = 7876;COMMIT;SELECT * FROM EMP WHERE EMPNO = 7876;7.2.4【训练1】CREATE OR REPLACE TRIGGER CHECK_TIMEBEFOREUPDATE OR INSERT OR DELETE ON EMPBEGIN IF (TO_CHAR(SYSDATE,DY) IN (SAT,SUN) OR TO_CHAR(SYSDATE,HH24)< 08 OR TO_CHAR(SYSDATE,HH24)>=17 THENRAISE_APPLICATION_ERROR(-20500,非法时间修改表错误！);END IF; END;UPDATE EMP SET SAL=3000 WHERE EMPNO=7369;【练习1】设计一个语句级触发器，限定只能对数据库进行修改操作，不能对数据库进行插入和删除操作。在需要进行插入和删除时，将触发器设置为无效状态，完成后重新设置为生效状态。CREATE OR REPLACE TRIGGER onlyupdateBEFOREUPDATE OR INSERT OR DELETE ON EMPBEGIN IF deleting or inserting thenRAISE_APPLICATION_ERROR(-20500,非法操作！);END IF; END;7.3【训练1】CREATE OR REPLACE TRIGGER NODROP_EMPBEFOREDROP ON SCHEMA BEGINIF Sys.Dictionary_obj_name=EMP THENRAISE_APPLICATION_ERROR(-20005,错误信息：不能删除emp表！);END IF; END;DROP TABLE emp;7.4【训练1】CREATE VIEW emp_name AS SELECT ename FROM emp;CREATE OR REPLACE TRIGGER change_name INSTEAD OF INSERT ON emp_nameDECLAREV_EMPNO NUMBER(4);BEGIN SELECT MAX(EMPNO)+1 INTO V_EMPNO FROM EMP; INSERT INTO emp(empno,ename) VALUES(V_EMPNO,:new.ename);END;INSERT INTO emp_name VALUES(BROWN);COMMIT;【训练2】CREATE OR REPLACE TRIGGER delete_from_enameINSTEAD OF DELETE ON emp_nameBEGIN RAISE_APPLICATION_ERROR(-20006,错误信息：不能在视图中删除emp表的雇员！);END;实验七创建触发器，进行表的同步复制CREATE OR REPLACE TRIGGER copytimebeforeINSert OF DELETE or UPDATE ON cc;BEGIN if inserting then insert into copynew values(:new id); elsif deleting then delete copynew where id=:old.id; else update copynew set id:=:new id where id=:old id; end if;END;出现问题解决方案（列出遇到的问题及其解决方法）