背景：

自动化测试往往会产生很多脏数据， 需要建立一种机制， 来定期删除数据

策略：建立触发器， 实时删除某些数据

Final:

1. 创建函数：delete_old_lalala_antities()

delete from lalala_antit where lalala_name like '%rrr_lalala_antities_automation1%' and lalala_antit_id <(select max(lalala_antit_id) from lalala_antit)-3;

创建触发器：

CREATE TRIGGER delete_old_lalala_antities AFTER INSERT ON lalala_antit 

FOR EACH ROW EXECUTE PROCEDURE delete_old_lalala_antities();

create trigger delete_old_lalala_antities after insert on lalala_antit for each statement execute procedure delete_old_lalala_antities();

查看创建的触发器：

https://www.postgresql.org/docs/12/plpgsql-trigger.html#PLPGSQL-DML-TRIGGER

Command:

select * from pg_trigger; 查看触发器

\df+ ------- 查看function

\dy+ -------查看事件触发器

\sf asdf2() ----查看function 详se

DROP TRIGGER asdf2 ON lalala_antit; ----删除trigger. Drop 

insert into lalala_antit(lalala_name) values ('hello'). ------ 插入数据命令

改动一个function 

CREATE OR REPLACE FUNCTION delete_old_lalala_antities () 

 RETURNS TRIGGER AS $delete_antit$

 BEGIN delete from lalala_antit where lalala_name like '%rrr_lalala_antities_automation1%' and lalala_antit_id <(select max(lalala_antit_id) from lalala_antit)-10;

return NULL; END; 

$delete_antit$ LANGUAGE plpgsql

$delete_antit$ LANGUAGE plpgsql