5.43.txt

delphi renyuanguanlixinxioxitong

ALTER TABLE employee ADD 
  CONSTRAINT fk_deptno FOREIGN KEY(departmentno) 
  REFERENCES department(departmentno) ON DELETE CASCADE;

CREATE OR REPLACE TRIGGER tr_update_cascade
AFTER UPDATE OF departmentno ON department 
FOR EACH ROW
BEGIN
  UPDATE employee SET departmentno=:new.departmentno
  WHERE departmentno=:old.departmentno;
END tr_update_cascade;