【OCP最新题库解析(052)--题42】 which is true about invalid PL/SQL

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发布于 2019-09-30 18:21:20

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发布于 2019-09-30 18:21:20

文章被收录于专栏：小麦苗的DB宝专栏

该系列专题为2018年4月OCP-052考题变革后的最新题库。题库为小麦苗解答，若解答有不对之处，可留言，也可联系小麦苗进行修改。

注：OCP-052最新题库完整详细解答版请联系小麦苗私聊。解题不易，请大家尊重原创。

题目

which is true about invalid PL/SQL objects?

A. They are automatically recompiled against the new definition of a referenced object when they are called.

B. They must be manually recompiled before they can be used if a DDL is performed on a table that is referenced in the PL/SQL object.

C. They are automatically recompiled against the new definition of a referenced object at the same time as the referenced object is modified.

D. They can be manually recompiled only by using SQL commands.

答案

Answer：A

失效的PL/SQL对象在下一次执行时会自动进行编译操作，排除B、C和D。

实验如下：

LHR@OCPLHR1> create table test_ddl(id number);
Table created.
LHR@OCPLHR1> create or replace procedure pro_test_ddl as begin insert into test_ddl(id) values(1);commit; end;
  2  /
Procedure created.
LHR@OCPLHR1> show errors
No errors.
LHR@OCPLHR1> select status from user_objects where object_name='PRO_TEST_DDL';
STATUS
-------
VALID
LHR@OCPLHR1> alter table test_ddl add name varchar2(10);
Table altered.
LHR@OCPLHR1> select status from user_objects where object_name='PRO_TEST_DDL';
STATUS
-------
VALID
LHR@OCPLHR1> alter table test_ddl drop column id;
Table altered.
LHR@OCPLHR1> select status from user_objects where object_name='PRO_TEST_DDL';
STATUS
-------
INVALID
LHR@OCPLHR1> alter table test_ddl add id number;
Table altered.
LHR@OCPLHR1> select status from user_objects where object_name='PRO_TEST_DDL';
STATUS
-------
INVALID
LHR@OCPLHR1> exec PRO_TEST_DDL;
PL/SQL procedure successfully completed.
LHR@OCPLHR1> select status from user_objects where object_name='PRO_TEST_DDL';
STATUS
-------
VALID

About Me：小麦苗

● 本文作者：小麦苗，只专注于数据库的技术，更注重技术的运用

● 作者博客地址：http://blog.itpub.net/26736162/abstract/1/

● 本系列题目来源于作者的学习笔记，部分整理自网络，若有侵权或不当之处还请谅解

● 题目解答若有不当之处，还望各位朋友批评指正，共同进步

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