Oracle Oracle Certifications 1Z0-874 Questions & Answers

• Question 61:

  What will be the results of the following query?

  mysql> SELECT * FROM CountryLanguage PROCEDURE ANALYSE(10, 256)\G

  A. For each column of the CountryLanguage table, the minimum and maximum values will be listed.

  B. For each column of the CountryLanguage table, the average value or average length will be listed.

  C. For each column of the CountryLanguage table, a data type will be suggested that is just large enough to hold the data.

  D. For each column of the CountryLanguage table, the data type will be changed to one that is just large enough to hold the data.

  E. It will result in an error.

  Correct Answer: CD

• Question 62:

  Does the ordering of tables shown in an EXPLAIN output have any significance? Why?

  A. Yes, it determines the table from which data will read first.

  B. No, it sorts them alphabetically.

  C. Yes, it sorts by the most optimized to the least optimized.

  D. No, the order is determined by the order in which tables are specified in the statement being EXPLAINed.

  Correct Answer: A

• Question 63:

  Consider the following: mysql> EXPLAIN SELECT Name FROM Country WHERE Population BETWEEN 1 AND 10000\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: Country type: range possible_keys: i_pop key: i_pop key_len: 4 ref: NULL rows: 10 Extra: Using where What is the meaning of the range value of the type column?

  A. There is a range of indexes that can be used.

  B. The type of index uses the range algorithm.

  C. The index is used to select rows that fall between a range of index values.

  D. The optimizer has determined that only data from the very beginning or the very end of the table is needed

  Correct Answer: C

• Question 64:

  Consider the following: mysql> EXPLAIN SELECT * FROM City WHERE CountryCode = 'USA'\G *************************** 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 Which of the following best describes the meaning of the "id" column in the output from EXPLAIN?

  A. Which process it is running as.

  B. Which SELECT the row refers to.

  C. It is just an incremental number to identify the rows from the output.

  Correct Answer: C

• Question 65:

  Consider the following:

  mysql> EXPLAIN SELECT Name FROM City WHERE CountryCode = (SELECT Code FROM Country

  WHERE Name = 'United States')\G

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

  id: 1

  select_type: PRIMARY

  table: City type: ALL

  possible_keys: NULL

  key: NULL

  key_len: NULL

  ref: NULL

  rows: 4079

  Extra: Using where

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

  A. The query has a subquery.

  B. It is the first SELECT in a subquery.

  C. The outer select is the SELECT referred to in the output row.

  D. The inner select is the SELECT referred to in the output row.

  Correct Answer: C

• Question 66:

  Which of the following statements are true regarding wildcards in the host name of an account specification?

  A. The '%' character is used to match any number of characters or numbers

  B. The '*' character is used to match any number of characters or numbers

  C. The '_' character is used to match any number of characters or numbers

  D. The '.' character is used to match any single character or number

  E. Wildcards may be used to match any number of characters at the beginning of the host name or IP address only

  F. Wildcards may be used to match any number of characters at the end of the host name or IP address only

  G. Wildcards may be used to match any number of characters anywhere in the host name or IP address

  Correct Answer: AFG

• Question 67:

  Consider the following EXPLAIN of a simple Join: mysql> EXPLAIN SELECT CountryList.Name, CityList.Name, CityList.Population -> FROM CountryList JOIN CityList ON CountryList.Code = CityList.Country -> WHERE CityList.Population > 8000000\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: CountryList

  type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 239 Extra: *************************** 2. row *************************** id: 1 select_type: SIMPLE table: CityList type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 4079 Extra: Using where How many rows need to be examined to perform the join?

  A. 239, the number of rows in the first table

  B. 4079, the number of rows in the second table

  C. 2159, the average of both numbers

  D. 4318, the sum of both numbers

  E. 974881, the product of both numbers

  Correct Answer: E

• Question 68:

  Consider the following EXPLAIN output. mysql> EXPLAIN SELECT Name FROM City WHERE Population > 8000000\G *************************** 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 Which of the following statements are true?

  A. The query cannot be optimized any better.

  B. No index could be used to perform the query.

  C. All 4079 rows of the table need to examined.

  D. The Name column should be indexed.

  E. The Population column should be indexed.

  Correct Answer: B

• Question 69:

  Why should you be selective when granting the SUPER privilege to an account?

  A. Because it allows a client to kill other client connections.

  B. Because it allows a client to shutdown the server.

  C. Because it allows changing of the server runtime configuration.

  D. Because it allows client accounts to takeover other client accounts.

  Correct Answer: A

• Question 70:

  Which of the following is/are valid reasons to consider using --skip-networking?

  A. Your server is not networked to other servers.

  B. You do not have a need for remote clients to connect.

  C. You have a need for remote clients to connect.

  D. You are not going to use replication or clustering.

  Correct Answer: B