在Oracle数据库的用户下,一张表需要做读写控制,只能读和写,不能删除和修改。开发人员开始想从用户权限上去实现。经过一番讨论
在Oracle数据库的用户下,一张表需要做读写控制,只能读和写,不能删除和修改。开发人员开始想从用户权限上去实现。
经过一番讨论,判读从权限上去实现该需求是不合适的。
这个用户下很多表,根本不会被一个人控制的。用户本身有一个权限组resource,可以对其下所有表进行增删改查。
如果要用权限来实现,那么就得将这个组去掉。这样,该用户下的其他表就得一个一个授权。还得考虑到以后新建的表。如何处理又是个问题。
因此,判断该解决方式不合适。
这种单独一张表的读写控制,不知道审计能不能实现。我想到一种另外的控制方法,让表只能读写,不能删改。这个方法就是利用触发器。
在表的每一行纪录进行增删改之前做判断,如果是增,则不做任何处理,如果是删除或者修改,直接rollback。
这样就实现了这种读写控制。
触发器代码如下:
create or replace trigger trg_test_insert_select
before insert or update or delete on t_test
for each row
declare
-- local variables here
begin
CASE
WHEN INSERTING THEN
DBMS_OUTPUT.PUT_LINE('Inserting');
WHEN UPDATING THEN
DBMS_OUTPUT.PUT_LINE('Updating');
rollback;
WHEN DELETING THEN
DBMS_OUTPUT.PUT_LINE('Deleting');
rollback;
END CASE;
end trg_test_insert_select;
测试结果如下:
SQL> insert into t_test(a) select sysdate from dual;
1 row inserted
SQL> commit;
Commit complete
SQL> delete from t_test;
delete from t_test
ORA-04092: ROLLBACK 不能在触发器中
ORA-06512: 在 "SCOTT.TRG_TEST_INSERT_SELECT", line 12
ORA-04088: 触发器 'SCOTT.TRG_TEST_INSERT_SELECT' 执行过程中出错
SQL> update t_test set a=sysdate+1;
update t_test set a=sysdate+1
ORA-04092: ROLLBACK 不能在触发器中
ORA-06512: 在 "SCOTT.TRG_TEST_INSERT_SELECT", line 9
ORA-04088: 触发器 'SCOTT.TRG_TEST_INSERT_SELECT' 执行过程中出错
注意,在应用开发时,需要将这个表的操作进行封装,,异常捕获很重要。
推荐阅读:
Oracle中的角色和权限授予
Oracle收集用户的权限
Oracle权限总结
Oracle查询指定用户有权限的所有表
修改文件目录权限导致数据库连接报错ORA-12547

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