DELETE事件触发器函数
最近更新时间: 2024-06-12 15:06:00
限制TDSQL PG记录不能被删除。
postgres=# CREATE OR REPLACE FUNCTION t_trigger_delete_trigger_func() RETURNS trigger AS
postgres-# $$
postgres$# BEGIN
postgres$# #不准许t_trigger.nc值为 TDSQL PG
postgres$# IF OLD.nc = 'TDSQL PG' THEN
postgres$# RETURN NULL;
postgres$# --RAISE EXCEPTION 'TDSQL PG不能被删除';
postgres$# END IF;
postgres$# RETURN OLD;
postgres$# END;
postgres$# $$
postgres-# LANGUAGE plpgsql;
CREATE FUNCTION
postgres=# CREATE TRIGGER t_trigger_delete_trigger BEFORE DELETE ON t_trigger FOR EACH ROW EXECUTE PROCEDURE t_trigger_delete_trigger_func();
CREATE TRIGGER
postgres=# INSERT INTO t_trigger VALUES(2,'TDSQL PG');
INSERT 0 1
postgres=# SELECT * t_trigg
postgres=# SELECT * FROM t_trigger ;
id | nc
----+-------------------------
1 | TDSQLPG_0.426093454472721
2 | TDSQL PG
(2 rows)
postgres=# DELETE FROM t_trigger WHERE id=2;
DELETE 0
postgres=# SELECT * FROM t_trigger ;
id | nc
----+-------------------------
1 | TDSQLPG_0.426093454472721
2 | TDSQL PG
(2 rows)