题目内容

迈捷邮件系统中,关于回收站的作用正确的有()

A. 在彻底删除前,保存已经删除的邮件
B. 从回收站里删除数据后,仍然可以找回
C. 可以防止误删除邮件,方便邮件找回
D. 如果彻底删除了邮件,是不会保存在回收站里的

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施工中井盖开启时,应在井盖旁设置醒目的反光锥形标志物。

A. 正确
B. 错误

电缆通过孔洞、管子或楼板时,两侧应设专人监护。入口侧应防止电缆被卡或手被带入孔内,出口侧的人员不得在()接引。

User SCOTT executes the following command on the EMP table but has not issued COMMIT, ROLLBACK, orany data definition language (DDL) command: SQL> SELECT ename FROM emp WHERE job=’CLERK’ FOR UPDATE OF empno; SCOTT has opened another session to work with the database instance. Which three operations would waitwhen issued in SCOTT’s second session()

A. LOCK TABLE emp IN SHARE MODE;
B. LOCK TABLE emp IN EXCLUSIVE MODE;
C. UPDATE emp SET sal=sal*1.2 WHERE job=ANAGER?UPDATE emp SET sal=sal*1.2 WHERE job=?ANAGER?
D. INSERT INTO emp(empno,ename) VALUES (1289,’Harry’);
E. SELECT ename FROM emp WHERE job=’CLERK’ FOR UPDATE OF empno

简述南戏。

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