It is ignored by the query optimizer.
It is not used while the index is being rebuilt.
The index cannot be rebuilt， and has to be re-created.
The index is automatically rebuilt when used the next time
第1题：
You have altered a non-unique index to be invisible to determine if queries execute within an acceptable response time without using this index.Which two are possible if table updates are performed which affect the invisible index columns?（）
A. The index remains invisible.
B. The index is not updated by the DML statements on the indexed table.
C. The index automatically becomes visible in order to have it updated by DML on the table.
D. The index becomes unusable but the table is updated by the DML.
E. The index is updated by the DML on the table.
第2题：
Given the following table definition: STOCK: item VARCHAR(30) status CHAR(1) quantity INT price DEC(7,2) If items are indicated to be out of stock by setting STATUS to NULL and QUANTITY and PRICE to zero, which of the following statements would be used to update the STOCK table to indicate that all the items whose description begins with the letter "S" are out of stock?（）
第3题：
Which of the following statements about ORACLE is (are) correct?
Ⅰ.ORACLE follows SQL standard
Ⅱ.ORACLE database defines two logical types: table and view
A．Ⅰonly
B．Ⅱ only
C．Ⅰ and Ⅱ
D．none of the above
第4题：
Examine the following PL/SQL block： DECLARE my_plans pls_integer； BEGIN my_plans ：= DBMS_SPM.LOAD_PLANS_FROM_CURSOR_CACHE （sql_id=> ？9twu5t2dn5xd？； END； Which statement is true about the plan being loaded into the SQL plan baseline by the above command？（）
第5题：
Examine the following output： SQL> SELECT index_name，status FROM dba_indexes WHERE status=’UNUSABLE’； INDEX_NAME STATUS------------------------------ ----------- EIND UNUSABLE Which two statements about the above index are true（）
第6题：
A. SER_NO
B. ORDER_ID
C. STATUS
D. PROD_ID
E. ORD_TOTAL
F. Composite index on ORDER_ID and ORDER_DATE
第7题：
Which of the following dbx commands should be used to obtain a stack trace from a coredump file?（）
第8题：
A. It is loaded with the FIXED status.
B. It is loaded with the ACCEPTED status.
C. It is not loaded with the ENABLED status.
D.It is not loaded with the ACCEPTED status.
第9题：
Examine the SQL statement that creates ORDERS table: CREATE TABLE orders (SER_NO NUMBER UNIQUE, ORDER_ID NUMBER, ORDER_DATE DATE NOT NULL, STATUS VARCHAR2(10) CHECK (status IN ('CREDIT', 'CASH')), PROD_ID NUMBER REFERENCES PRODUCTS(PRODUCT_ID), ORD_TOTAL NUMBER, PRIMARY KEY (order_id, order_date)); For which columns would an index be automatically created when you execute the above SQL statement? （）
第10题：
Examine the command that is used to create a table： SQL> CREATE TABLE orders（oid NUMBER（6） PRIMARY KEY， odate DATE， ccode NUMBER（6）， oamt NUMBER（10，2）） TABLESPACE users； Which two statements are true about the effect of the above command） （）