Question

oracle触发器实现级联删除

老师要求用触发器，删除联系人表中的一行，把残疾人，老年人表中与联系人表要删除的那一行身份证号相符的一起删除，但是是先删老年人表，但是这些表中未必有那一行身份证号相符的
我写的编译通过但是报警了，且后期试了不好使，该怎么写？
create or replace trigger naomi.delete_contacts
before delete on CONTACTS
for each row
begin
delete from Elderly where people_id = :old.people_id;
delete from Soldier where people_id = :old.people_id;
delete from disabled where people_id = :old.people_id;
delete from student where people_id = :old.people_id;
end;

Answer 1

使用级联删除+触发器可以搞定你的需求。\r\n父表A 子表B 备份表C\r\n命令如下:\r\ncreate table A \r\n(\r\n dept_ID number primary key,\r\n dept_name varchar2(10)\r\n);\r\n\r\ncreate table B\r\n(\r\n no number primary key,\r\n name varchar2(10),\r\n dept_id number\r\n);\r\n\r\nALTER TABLE WWJ.B ADD CONSTRAINT FK_B FOREIGN KEY (DEPT_ID) REFERENCES WWJ.A (DEPT_ID) ON DELETE CASCADE ENABLE VALIDATE;\r\n\r\nCREATE OR REPLACE TRIGGER WWJ.TR_B_01\r\nBEFORE DELETE\r\nON WWJ.B \r\nREFERENCING NEW AS New OLD AS Old\r\nFOR EACH ROW\r\nBEGIN\r\n INSERT INTO C VALUES(:old.no,:old.name,:old.dept_id);\r\nEND;