一般来说，我们未来阻止用户删除或者清空表以及数据， 可以直接从权限下手，给他少量的权限即可。

t_girl=# create role ytt3 with login connection limit 1 password 'ytt3'; CREATE ROLE t_girl=# alter schema ytt owner to ytt3; ALTER SCHEMA t_girl=# grant select on all tables in schema ytt to ytt3; GRANT

bash-4.1$ psql -U ytt3 t_girl psql (9.3.4) Type "help" for help. t_girl=> truncate table j2; ERROR: permission denied for relation j2

t_girl=# \sf prevent_truncate CREATE OR REPLACE FUNCTION public.prevent_truncate() RETURNS trigger LANGUAGE plpgsql AS $functio$ BEGIN RAISE EXCEPTION 'Prevent "%" to be truncated!', TG_TABLE_SCHEMA||TG_TABLE_NAME; RETURN NEW; END; $function$

t_girl=# \d j2 Table "ytt.j2" Column | Type | Modifiers --------+---------+----------- id | integer | str2 | text | Triggers: trigger_truncate_before BEFORE TRUNCATE ON j2 FOR EACH STATEMENT EXECUTE PROCEDURE ytt.prevent_truncate()

t_girl=# truncate table j2; ERROR: Prevent "ytt.j2" to be truncated!

mysql> truncate table j2; ERROR 1142 (42000): DROP command denied to user 'ytt3'@'localhost' for table 'j2'

+------------------------------------+ | Error | +------------------------------------+ | Prevent t_girl.j2 to be truncated! | +------------------------------------+ 1 row in set (0.00 sec)