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OCP考试题解析_007:DDL和ROLLBACK

发布时间: 2013-03-01 18:33:02 作者: rapoo

OCP考题解析_007:DDL和ROLLBACK
DDL为什么不能rollback?

在Oracle中DDL语句将转化为对数据字典表的DML语句;比如,一个简单的修改表的DDL语句,会导致Oracle在后台通过递归SQL语句进行大量的查询和修改的操作

--DDL伪代码

Q: 4 Evaluate the set of SQL statements:CREATE TABLE dept(deptno NUMBER(2),dname VARCHAR2(14),loc VARCHAR2(13));ROLLBACK;DESCRIBE DEPTWhat is true about the set?A. The DESCRIBE DEPT statement displays the structure of the DEPT table. B. The ROLLBACK statement frees the storage space occupied by the DEPT table. C. The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist. D. The DESCRIBE DEPT statement displays the structure of the DEPT table only if there is a COMMIT statement introduced before the ROLLBACK statement. Answer: A  


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