原文链接：【云贝教育】Oracle 19c OCP 082题库解析(4) - 课程体系 - 云贝教育 (yunbee.net)
考试科目：1Z0-082
考试题量：90
通过分数：60%
考试时间：150min
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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
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