oracle实验记录 (事务控制)
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commit;
rollback;
savepoint;
rollback to savepoint;
set transaction;
set constraints;
set transaction read write(defalut)
set transaction read only不可以DML
SQL> set transaction name 'userxh';~~~~~~~事务命名
Transaction set.
SQL> insert into t1 values(1);
1 row created.
SQL> select name from v$transaction where name='userxh';
NAME
--------------------------------------------------------------------------------
userxh
SQL> set transaction read only;~~~~~~~~等上一个结束才可以设置新的
set transaction read only
*
ERROR at line 1:
ORA-01453: SET TRANSACTION must be first statement of transaction
SQL> commit;~~~~~~~~~~~userxh事务以commit 结束(or rollback)
Commit complete.
SQL> set transaction read only;~不可以DML
Transaction set.
SQL> insert into t1 values(1);
insert into t1 values(1)
*
ERROR at line 1:
ORA-01456: may not perform. insert/delete/update operation inside a READ ONLY
transaction
select ,alter system ,alter session可以
set transaction read write(default)
SQL> commit;(提交后 下一个TRANSACTION 自动为read write)
Commit complete.
set transaction isolation level read committed(default) 提供一致读
会出现不可重复读,幻象读(与第一读数据不一样,有新数据)
SQL> conn / as sysdba