B-tree
bitmap
reverse key
function based
第1题：
In which situations does the Oracle Data Pump use external tables and not the direct path load whileexporting a table（）
第2题：
A warehouse fact table in your Oracle 12c Database is range-partitioned by month and accessed frequently with queries that span multiple partitions The table has a local prefixed, range partitioned index. Some of these queries access very few rows in some partitions and all the rows in other partitions, but these queries still perform a full scan for all accessed partitions. This commonly occurs when the range of dates begins at the end of a month or ends close to the start of a month. You want an execution plan to be generated that uses indexed access when only a few rows are accessed from a segment, while still allowing full scans for segments where many rows are returned. Which three methods could transparently help to achieve this result?（）
第3题：
An index called ORD_CUSTNAME_IX has been created on the CUSTNAME column in the ORDERS table using the following command:SQL>CREATE INDEX ord_custname_ix ON orders(custname);The ORDERS table is frequently queried using the CUSTNAME column in the WHERE clause.You want to check the impact on the performance of the queries if the index is not available. You do not want the index to be dropped or rebuilt to perform this test.Which is the most efficient method of performing this task?（）
A. disabling the index
B. making the index invisible
C. making the index unusable
D. using the MONITORING USAGE clause for the index
第4题：
The ST_INFO master table has millions of rows that are updated very rarely. It has a STATE_CODE column that contains the value for 25 states. The table is frequently queried on the STATE_CODE column. Which type of index would you suggest to improve the query performance？（）
第5题：
An index called ORD_CUSTNAME_IX has been created on the CUSTNAME column in the ORDERS table using the following command： SQL>CREATE INDEX ord_custname_ix ON orders（custname）； The ORDERS table is frequently queried using the CUSTNAME column in the WHERE clause. You want to check the impact on the performance of the queries if the index is not available. You do not want the index to be dropped or rebuilt to perform this test. Which is the most efficient method of performing this task？（）
第6题：
You work in a company which uses SQL Server 2008. You are the administrator of the company database. Now you are in charge of a SQL Server 2008 instance. There is a database named named Dworks in the instance. The Dworks table has a table named BillDetails which has a clustered primary key named BillId on the BillId column. The BillDetails table has a single XML column named GoodsDetails. The XML column has an XML index and XML data are stored in this XML column. A new column named GoodsID is added to the BillDetails table. GoodsID must be included in the primary key. So what action should you perform to achieve this goal？（）
第7题：
The EMPLOYEES table has these columns: LAST NAME VARCHAR2(35) SALARY NUMBER(8,2) HIRE_DATE DATE Management wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement: ALTER TABLE EMPLOYEES MODIFY ( SALARY DEFAULT 5000); What is true about your ALTER statement?（）
第8题：
A. Column definitions cannot be altered to add DEFAULT values.
B. A change to the DEFAULT value affects only subsequent insertions to the table.
C. Column definitions cannot be altered at add DEFAULT values for columns with a NUMBER data type.
D. All the rows that have a NULL value for the SALARY column will be updated with the value 5000.
第9题：
As a result of performance analysis， you created an index on the prod_name column of the prod_det table， which contains about ten thousand rows. Later， you updated a product name in the table. How does this change affect the index？（）
第10题：
You need to change the definition of an existing table. The COMMERCIALS table needs its DESCRIPTION column changed to hold varying length characters up to 2000 bytes. The column can currently hold 1000 bytes per value. The table contains 20000 rows. Which statement is valid?（）