驗(yàn)證一個(gè)052考試題
8 、Examine the following statement:
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SQL> ALTER TABLE SALES MODIFY CONSTRAINT pk DISABLE VALIDATE;
Which three statements are true?
A)Rows may be inserted into the table.
B) The PK index is made unusable.
C)The PK index is dropped.
D)The constraint is still enforced for updated rows.
E)The constraint is still enforced for inserted rows.
Answer:CDE
--=====================
SQL> create table tt(id int primary key) ;
表已創(chuàng)建。
SQL> desc dba_constraints
名稱 是否為空? 類型
----------------------------------------- -------- ----------------------------
OWNER VARCHAR2(60)
CONSTRAINT_NAME NOT NULL VARCHAR2(30)
CONSTRAINT_TYPE VARCHAR2(1)
TABLE_NAME NOT NULL VARCHAR2(30)
SEARCH_CONDITION LONG
R_OWNER VARCHAR2(60)
R_CONSTRAINT_NAME VARCHAR2(30)
DELETE_RULE VARCHAR2(9)
STATUS VARCHAR2(8)
DEFERRABLE VARCHAR2(14)
DEFERRED VARCHAR2(9)
VALIDATED VARCHAR2(13)
GENERATED VARCHAR2(14)
BAD VARCHAR2(3)
RELY VARCHAR2(4)
LAST_CHANGE DATE
INDEX_OWNER VARCHAR2(30)
INDEX_NAME VARCHAR2(30)
INVALID VARCHAR2(7)
VIEW_RELATED VARCHAR2(14)
SQL> SELECT CONSTRAINT_NAME,CONSTRAINT_type from dba_constraints where table_name='TT';
CONSTRAINT_NAME C
------------------------------ -
SYS_C006993 P
SQL> alter table tt modify constraint SYS_C006993 disable validate;
表已更改。
SQL> SELECT CONSTRAINT_NAME,CONSTRAINT_type,status from dba_constraints where table_name='TT';
CONSTRAINT_NAME C STATUS
------------------------------ - --------
SYS_C006993 P DISABLED
SQL> SELECT CONSTRAINT_NAME,CONSTRAINT_type,status,validated from dba_constraints where table_name='TT';
CONSTRAINT_NAME C STATUS VALIDATED
------------------------------ - -------- -------------
SYS_C006993 P DISABLED VALIDATED
SQL> SELECT CONSTRAINT_NAME,CONSTRAINT_type,status,validated,index_name from dba_constraints where table_name='TT';
CONSTRAINT_NAME C STATUS VALIDATED
------------------------------ - -------- -------------
INDEX_NAME
------------------------------
SYS_C006993 P DISABLED VALIDATED
SQL> set linesize 120
SQL> SELECT CONSTRAINT_NAME,CONSTRAINT_type,status,validated,index_name from dba_constraints where table_name='TT';
CONSTRAINT_NAME C STATUS VALIDATED INDEX_NAME
------------------------------ - -------- ------------- ------------------------------
SYS_C006993 P DISABLED VALIDATED
SQL> select index_name from dba_indexes where table_name='TT';
未選定行
SQL> insert into tt values(1);
insert into tt values(1)
*
第 1 行出現(xiàn)錯(cuò)誤:
ORA-25128: 不能對(duì)帶有禁用和驗(yàn)證約束條件 (XYS.SYS_C006993) 的表進(jìn)行插入/更新/刪除
SQL>
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