东软学习，oracle函数与触发器

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--1.无参函数CREATE OR REPLACE FUNCTION func1 RETURN VARCHAR2       IS    BEGIN      RETURN '欢迎你:'||USER||',现在是:'||to_char(SYSDATE,'yyyy-mm-dd');    END func1;--调用测试  BEGIN  dbms_output.put_line(func1);END;--有参函数SELECT * FROM emp;CREATE OR REPLACE FUNCTION getWorkTime(hiredate DATE) RETURN NUMBER     ISBEGIN  RETURN trunc(months_between(SYSDATE,hiredate)/12);END getWorkTime;SELECT ename,job,getWorkTime(hiredate) FROM emp;--触发器--语句触发器(select/insert/update/delete)CREATE OR REPLACE TRIGGER trg_dept BEFORE INSERT OR UPDATE OR DELETE ON dept DECLARE  BEGIN   dbms_output.put_line(USER||','||to_char(SYSDATE,'yyyy-mm-dd')||',对dept进行操作。'); END trg_dept;UPDATE dept SET dname='测试' WHERE deptno=60;INSERT INTO dept VALUES(23,'触发器','数据库');--行触发器(FOR EACH ROW)--before触发器--伪记录 :NEW  :OLD--3个条件谓词：INSERTING  UPDATING  DELETINGCREATE OR REPLACE TRIGGER trg_dept_before       BEFORE INSERT OR UPDATE OR DELETE ON dept       FOR EACH ROWDECLARE       v_now VARCHAR2(50);BEGIN       v_now:=to_char(SYSDATE,'yyyy-mm-dd hh24:mi:ss');              CASE         WHEN INSERTING  THEN           dbms_output.put_line(v_now||'对dept表进行了添加操作');           dbms_output.put_line('添加的数据:'||:new.deptno||','||:new.dname||','||:new.loc);         WHEN UPDATING THEN           dbms_output.put_line(v_now||'对dept表进行了修改操作');           dbms_output.put_line('修改之前的数据:'||:old.deptno||','||:old.dname||','||:old.loc);           dbms_output.put_line('修改之后的数据:'||:new.deptno||','||:new.dname||','||:new.loc);         WHEN DELETING THEN           dbms_output.put_line(v_now||'对dept表进行了删除操作');           dbms_output.put_line('删除的数据:'||:old.deptno||','||:old.dname||','||:old.loc);       END CASE;END trg_dept_before;INSERT INTO dept VALUES(24,'触发器4','数据库4');UPDATE dept SET dname='测试' WHERE deptno=24;DELETE FROM dept WHERE deptno=24;COMMIT;--实现SQL Server中标识列效果CREATE SEQUENCE seq_dept_deptno INCREMENT BY 1 START WITH 100 MAXVALUE 999999 NOCYCLE;--触发器（从序列里面取值，并且在insert语句进行使用CREATE OR REPLACE TRIGGER trg_dept_before_increment   BEFORE INSERT ON dept FOR EACH ROWBEGIN  SELECT seq_dept_deptno.nextval INTO :new.deptno FROM dual;END trg_dept_before_increment;INSERT INTO dept (dname,loc) VALUES('序列','序列');--INSERT INTO dept (deptno,dname,loc) VALUES(seq_dept_deptno.nextval,'序列','序列');COMMIT;SELECT * FROM dept;
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