最新的MYSQL 1Z0-874免費考試真題

問題1

Consider the following:
mysql> EXPLAIN SELECT * FROM City WHERE CountryCode = 'USA'
*************************** 1. row ***************************
id: 1
select_type: SIMPLE table: City
type: ALL
possible_keys: NULL
key: NULL
key_len: NULL
ref: NULL
rows: 4079
Extra: Using where
What does the possible_keys column in this output denote?

A. Whether you are using any indexes in your query.

B. Whether there are any indexes on the table(s) you are querying.

C. If it is possible for you to include any indexes in your query.

D. If there are any indexes you may be able to use.

正確答案: D

問題2

Which of the following is true of the table cache if you mainly run simple queries on many tables?

A. The table cache should be decreased.

B. The table cache should not be changed.

C. The table cache should be increased.

正確答案: C

問題3

Which of the following are methods to improve performance? (Choose two)

A. Moving less needed parts of the MySQL install such as the documentation or the test files to different disks pointed to by a symbolic link.

B. Spreading whole databases to different disks pointed to by a symbolic link.

C. Moving the MySQL utilities such as mysqladmin to different disks pointed to by a symbolic link.

D. Spreading single tables to different disks pointed to by a symbolic link.

正確答案: B,D

問題4

Consider the following: mysql> EXPLAIN SELECT DISTINCT City.id,City.name -> FROM City,Country -> WHERE Country.Name IN ('United States','Canada','Mexico') -> AND City.CountryCode=Country.Code -> ORDER BY name *************************** 1. row *************************** id: 1 select_type: SIMPLE table: City type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 4079 Extra: Using temporary; Using filesort *************************** 2. row *************************** id: 1 select_type: SIMPLE table: Country type: eq_ref possible_keys: PRIMARY key: PRIMARY
key_len: 3
ref: world.City.CountryCode
rows: 1
Extra: Using where;
Distinct
Which of the following best describes the meaning of the values in the ref columns?

A. City.CountryCode is used to sort what rows are returned from the City table.

B. No indexed columns are used to choose rows from City and the City.CountryCode column is used to reference rows in the Country table.

C. No index columns are used to choose rows from Country and the City.CountryCode column is used to reference rows in the City table.

正確答案: B

問題5

Which of the following statements best describe the key buffer? (Choose two)

A. It caches index blocks for MyISAM tables only.

B. It is set on a per-connection basis.

C. It caches index blocks for all storage engine tables.

D. It is a global buffer.

E. It caches index blocks for InnoDB tables only.

正確答案: A,D

問題6

Granting access to the mysql database...

A. Should only be done on administrator accounts.

B. Should never be done for any users.

C. Should be done for anyone needing to create views

D. Should always be done for all users.

正確答案: A

問題7

Which of the following best describes why InnoDB tables should always have primary keys and why they should be short?

A. Because InnoDB uses primary keys to locate tables, and shorter keys make quicker lookups.

B. Because InnoDB uses primary keys to locate table rows, and shorter keys make quicker lookups.

C. Because InnoDB stores pointers in a log to all the primary keys and shorter keys make this log smaller.

正確答案: B

最新的MYSQL MySQL 5.0 Database Administrator Certified Professional Exam, Part II - 1Z0-874免費考試真題

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