CREATE OR REPLACE TRIGGER POSITION_NUMber
BEFORE UPDATE OR INSERT OR DELETE ON APPLIES
DeclARE
PRAGMA AUTONOMOUS_TRANSactION;
NUMber_OF_POSITIONS NUMber;
BEGIN
SELECT count(pnumber) INTO NUMber_OF_POSITIONS
FROM APPLIES WHERE anumber = :NEW.anumber;
IF( NUMber_OF_POSITIONS > 2 AND count(APPDATE) > 2 )
THEN
RAISE_APPLICATION_ERROR(-20000,'an Employee cannot apply for
more than two positions');
END IF;
END;
/
我试图创建一个触发器,如果申请人在同一天申请两个以上职位,该触发器将关闭,但是我不确定我将如何实现其日期方面。下面是一组关系方案