Oracle OCP 19c认证考试1Z0-082题库最新解析 第四题

4. You currently have an active transaction in your session and have been granted select access to V$TRANSACTION

In which three situations will re-executing this query still return a row but with a different XID

indicating a new transaction has started?

A.after successfully executing a TRUNCATE statement followed by a DML statement

B.after successfully executing a CREATE TABLE AS Select statement followed by a SELECT  FOR UPDATE statement

C.after successfully executing a CREATE TABLE statement followed by a CREATE INDEX statement

D.after successfully executing a commit or ROLLBACK followed by a DML statement

E.after successfully executing a DML statement following a failed DML statement

F. after successfully executing a commit or ROLLBACK followed by a Select statement

参考答案：ABD

解析:

题目问执行下面各个选项的操作之后，查询v$transaction表，返回一行，但是有不同的XID,只要commit rollback之后再在同一个表上发生事务，xid就会发生变化

A:TRUNCATE隐式提交，然后DML接着产生了一个事务

B:CREATE隐式提交，然后for update会产生一个事务

C:CREATE INDEX，虽说会修改数据字典产生事务，但是存在隐式提交，事务消失

D:提交或者回滚，事务结束，再进行DML，产生一个事务

E:失败的DML不产生事务

F:SELECT不产生事务