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91. Examine these facts about a database.
1. The database default tabpespace is USERS.
2. DEFERRED_SEGMENT_CREATION is TRUE.
3. The default tablespace of USER1 is tbs1.
4. USER1 has only these privileges:
•
CREATE SESSION
•
CREATE TABLE
•
UNLIMITED quota on tbs1
Examine these commands executed by USER1:
SQL> CREATE TABLE emp (eno NUMBER, ename VARCHAR2(20)) TABLESPACE TBS1;
Table created.
SQL> CREATE INDEX emp_inx ON emo(eno) TABLESPACE USERS;
Index created.
SQL> INSERT INTO emp VALUES (NULL,’Alan’);
What will be the outcome of the INSERT operation and why?
A) It will fail because an indexed column cannot have NULL values.
B) A row will be inserted into EMP and an index entry will be made into EMP_IDX.
C) It will fail because USER1 has no quota on USERS.
D) A row will be inserted into EMP and an index entry will be inserted into a virtual column of EMP
because USER1 has no quota an USERS.
E) A row will be inserted into EMP but no index entry will be made into EXP_IDX.
Answer：C
实验步骤：
SQL> show parameter defe
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
deferred_segment_creation boolean TRUE
SQL>
创建用户，指定默认表空间
SQL> create user user1 identified by user1 default tablespace tbs1;
User created.
授予相应权限
SQL> grant create session to user1;
Grant succeeded.
SQL> grant create table to user1;
Grant succeeded.
SQL> alter user user1 quota unlimited on tbs1;
User altered.
使用user1用户登录数据库
SQL> conn user1/user1
Connected.
创建表，指定表空间tbs1
SQL> cREATE TABLE emp (eno NUMBER, ename VARCHAR2(20)) TABLESPACE tbs1;
Table created.
创建索引，默认表空间users
SQL> CREATE INDEX emp_inx ON emp(eno) TABLESPACE USERS
Index created.
插入数据时报错提示没有权限，由此可以排除答案B\DE
SQL> insert into emp values(null,'alan');
insert into emp values(null,'alan')
*
ERROR at line 1:
ORA-01950: no privileges on tablespace 'USERS'
以下步骤验证数据插入失败原因，用户user1所创建的index没有写入users表空间数据的权限，而不是null和index的原因，排除答案A
SQL> drop index emp_inx;
Index dropped.
SQL> insert into emp values(null,'alan');
1 row created.
SQL> rollback
2 ;
Rollback complete.
SQL> drop index emp_inx;
drop index emp_inx
*
ERROR at line 1:
ORA-01418: specified index does not exist
SQL> CREATE INDEX emp_inx ON emp(eno) TABLESPACE ceshi;
Index created.
SQL> insert into emp values(null,'alan');
1 row created.
SQL>
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