Exit demo 1Z0-874 MySQL 5.0 Database Administrator Certified Professional Exam, Part II PDF format · free preview

Oracle 1Z0-874 - Questions & Answers

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Question 1
Single choice

Which of the following best describes what the master.info file contains and how it is used?

A.

It contains the values from the CHANGE MASTER statement.

B.

When the slave restarts it looks for which master to use from this file.

C.

It contains information about the master server, its slaves and its configuration.

D.

It is used by an administrator to determine what slaves connect to the master, and other information about the master server.

Question 2
Single choice

Which of the following statements are required to create a key cache of 4 MB, assign the MyISAM table world.
City to it and preload the index?

A.

mysql> SET GLOBAL city_cache.key_buffer_size = 4194304;mysql> CACHE INDEX world.City IN
city_cache;mysql> LOAD INDEX INTO CACHE world.City;

B.

mysql> ALTER TABLE world.city KEY_CACHE = 4194304;

C.

mysql> CREATE CACHE FOR world.City SIZE = 4194304;

D.

It is not possible to create a key cache for a specific MyISAM table, only the global key cache can be used.

Question 3
Single choice

How can the SHOW PROCESSLIST command be helpful when optimizing queries?

A.

It shows if a query is using an index or not.

B.

It shows how the server processes a query.

C.

If checked periodically, it can reveal queries that cause other queries to hang.

D.

It shows the percentage of processing power that each query is using on a server.

Question 4
Single choice

Consider the following:

mysql> EXPLAIN SELECT Name FROM Country WHERE Code = 'CAN'\G

*************************** 1. row ***************************

id: 1

select_type: SIMPLE

table: Country

type: const

possible_keys: PRIMARY

key: PRIMARY

key_len: 3

ref: const

rows: 1

Extra:

Which of the following best describes the meaning of the value of the type column?

A.

The table has exactly one row.

B.

Several rows may be read from the table.

C.

Only one row of all its rows need to be read.

Question 5
Single choice

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.

Question 6
Single choice

Which of the following best describes how the relay log works?

A.

It records the times when the slave connects to the master.

B.

When a slave receives a change from the master, it is recorded in the relay log first and processed later.

C.

When a slave receives a change from the master, it is processed first and then recorded in the relay log.

Question 7
Single choice

With replication, what on the master is used to send commands to the slave?

A.

The relay log.

B.

The binary log.

C.

The SQL Thread.

Question 8
Single choice

Given the following MyISAM table structure:

mysql> desc city;

+-------------+----------+------+-----+---------+----------------+

| Field | Type | Null | Key | Default | Extra |

+-------------+----------+------+-----+---------+----------------+

| ID | int(11) | | PRI | NULL | auto_increment |

| Name | char(35) | | | | |

| CountryCode | char(3) | | | | |
| District | char(20) | | | | |

| Population | int(11) | | MUL | 0 | |

+-------------+----------+------+-----+---------+----------------+

and the following SQL statement:

SELECT Population

FROM city

WHERE Population = 10000

ORDER BY Population

LIMIT 5;

Which of the following statements best describes how MySQL optimizer executes the query?

A.

The optimizer uses the primary key column ID to read the index values, then uses the index on Population to filter the results. The optimizer will always choose to use a unique index first, then use a secondary index if available.

B.

The optimizer uses the index on the Population column to search and filter the WHERE clause.
A temporary table is used to perform a filesort on the results, and then only 5 records are returned to the client.

C.

The optimizer uses the index on the Population column to search, filter and sort the Population column, then returns 5 records to the client. The optimizer does not need to read the data rows, and can return values from the index only, because the index contains just integer values that form a leftmost prefix for the key.

D.

The optimizer uses the index on the Population column to search, filter and sort the Population column, and returns 5 records to the client. The optimizer does not need to read the data rows, and can return values from the index only because only those columns where specified in the SELECT statement.

E.

The optimizer will never read data from disk, since MySQL caches both data and index in the key buffer.

Question 9
Single choice

The stored function year_to_date is created by the 'root'@'localhost' account as follows:

CREATE FUNCTION year_to_date ()

RETURNS DECIMAL(10,2)
SQL SECURITY DEFINER

BEGIN

...

END;

Within the routine body, a number of calculations are made on data in the financials table and the calculated value is returned. The only account which can access the financials table is 'root'@'localhost'.

If a client connects with the account 'joe'@'localhost' and calls the year_to_date function, what will happen?

A.

The function will always execute as if it was 'root'@'localhost' that invoked it since SQL SECURITY DEFINER has been specified.

B.

The function will not execute, as 'joe'@'localhost' does not have access to the financials table

C.

The function will not execute as SQL SECURITY DEFINER has been specified. It would execute if
instead SQL SECURITY INVOKER had been specified

D.

If the account 'joe'@'localhost' has the EXECUTE privilege on year_to_date, the function will complete

successfully

Question 10
Single choice

How can stored routines be used to check for constraints or legality of incoming data?

A.

They can make use of the VALIDATE DEFINER setting.

B.

They can not be used to check for constraints or legality of data.

C.

They can check and only perform an action if the incoming values match a specified value.

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