185.User SCOTT executes the following command on the EMP table but has not issued COMMIT, ROLLBACK,
来源:互联网 发布:手机检索专利软件 编辑:程序博客网 时间:2024/05/16 15:49
185.User SCOTT executes the following command on the EMP table but has not issued COMMIT,
ROLLBACK, or any 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
wait when issued in SCOTT's second session? (Choose three.)
A.LOCK TABLE emp IN SHARE MODE;
B.LOCK TABLE emp IN EXCLUSIVE MODE;
C.UPDATE emp SET sal=sal*1.2 WHERE job=MANAGER;
D.INSERT INTO emp(empno,ename) VALUES (1289,'Harry');
E.SELECT ename FROM emp WHERE job='CLERK' FOR UPDATE OF empno;
答案:ABE
解析:这个select ... for update 是在TX加上了S锁,在TM上增加了SX锁,
因此不能在TX上增加X锁,不能在TM上增加S、SSX、X锁
A:正确,这个相当于TMS锁
B:正确,这个是TM的X锁
C:这里只是TM的SX锁
D:和C一样
E:正确,这里是SX锁,锁的是不同的记录
ROLLBACK, or any 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
wait when issued in SCOTT's second session? (Choose three.)
A.LOCK TABLE emp IN SHARE MODE;
B.LOCK TABLE emp IN EXCLUSIVE MODE;
C.UPDATE emp SET sal=sal*1.2 WHERE job=MANAGER;
D.INSERT INTO emp(empno,ename) VALUES (1289,'Harry');
E.SELECT ename FROM emp WHERE job='CLERK' FOR UPDATE OF empno;
答案:ABE
解析:这个select ... for update 是在TX加上了S锁,在TM上增加了SX锁,
因此不能在TX上增加X锁,不能在TM上增加S、SSX、X锁
A:正确,这个相当于TMS锁
B:正确,这个是TM的X锁
C:这里只是TM的SX锁
D:和C一样
E:正确,这里是SX锁,锁的是不同的记录
0 0
- 185.User SCOTT executes the following command on the EMP table but has not issued COMMIT, ROLLBACK,
- User SCOTT executes the following command on the EMP table but has not issued COMMIT, ROLLBACK, or a
- The session of user SCOTT receives the following error after executing an UPDATE command on the EMP
- 186.User A executes the following command to drop a large table in your database: SQL> DROP TABLE tr
- 172.The session of user SCOTT receives the following error after executing an UPDATE command on the
- 37.You issued the following command to drop the PRODUCTS table:
- 1Z0-051 37. You issued the following command to drop the PRODUCTS table:
- 155.The user HR owns the EMP table. The user HR grants privileges to the user SCOTT by using this co
- ocp 047-40 User OE, the owner of the ORDERS table, issues the following command:
- 38.To make audit information more productive, the DBA executes the following command before starting
- 49.The ORDERS table belongs to the user OE. OE has granted the SELECT privilege on the ORDERS table
- 57.The CUSTOMERS table has the following structure:
- 95.The PRODUCTS table has the following structure:
- 104 User SCOTT wants to back out the transactions on the REGIONS table in his schema. As a DBA, whic
- 142.The user SCOTT owns the CUST table that is placed in the SALES tablespace. The user SCOTT opens
- 122 The user SYS creates a job by using the following command: BEGIN DBMS_SCHEDULER.CREATE_JOB ( job
- Create the User Scott Manually
- The effects of the TRUNCATE command on a table
- “去IOE” 之 MySQL与PostgreSQL的抉择
- 184.You suspect unauthorized data manipulation language (DML) operations on a particular table. You
- QGraphicsView框架容易忽视的坐标问题-“画布”QgraphicsScene到底放在了哪儿?
- ArrayList、Vector
- JQuery this和$(this)的区别及获取$(this)子元素对象的方法
- 185.User SCOTT executes the following command on the EMP table but has not issued COMMIT, ROLLBACK,
- cocoapods:常见错误总结+Mac OS 10.11
- struts2 图片上传 详解
- 生成一个集合的所有子集 Subset
- 关于解决android studio各种疑难杂症系列---- 工程的geadle版本跟当前环境不匹配
- TextView去掉自身自带的内边距
- [leetcode] 215. Kth Largest Element in an Array
- jquery 对 Json 的各种遍历
- 186.User A executes the following command to drop a large table in your database: SQL> DROP TABLE tr