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51.

The key declares that an index in one table is related to that in another is called _____________(a) primary(b) secondary(c) foreign(d) crossI got this question by my college professor while I was bunking the class.My question is from Perl DBI Overview topic in portion MySQL Programs Using Perl DBI and PHP of MySQL

Answer» CORRECT OPTION is (c) foreign

Explanation: In MYSQL, a foreign key is the one that facilitates index RELATIONS across tables. It declares that an index in one table is related to that in another and PLACE constraints.
Discussion
52.

The operator that does not perform relative-value comparisons is ______________(a) =(b) ==(c) =The question was posed to me in quiz.My question is taken from Perl DBI Overview topic in section MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

Right answer is (b) ==

The best explanation: The operators =, <>, >, >=, <, and <= perform relative value comparisons in MySQL. ‘==’ is not a VALID comparison OPERATOR in MySQL. Such operators are USEFUL in filtering information from a table.
Discussion
53.

What allows nesting one select statement into another?(a) nesting(b) binding(c) subquerying(d) encapsulatingThe question was asked in an interview for job.I want to ask this question from Perl DBI Overview topic in chapter MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

Correct ANSWER is (c) subquerying

The best EXPLANATION: The ‘subquerying’ support provided by MySQL is a capability that ALLOWS writing ONE ‘SELECT’ statement within parentheses and nesting within another. This allows logically selecting CONTENT from tables.
Discussion
54.

The statement to remove indexes on tables is ______________(a) DROP INDEX(b) DELETE INDEX(c) REMOVE INDEX(d) FLUSH INDEXI got this question during an interview for a job.The query is from Perl DBI Overview in chapter MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

Correct ANSWER is (a) DROP INDEX

Explanation: MYSQL PROVIDES statements to change the structure of tables. To add or remove the indexes on the EXISTING database tables, the ‘CREATE INDEX’ and ‘DROP INDEX’ tables are used.
Discussion
55.

Which variable returns code from operations that return true or false?(a) $rc(b) $rv(c) $rows(d) $aryI got this question by my school teacher while I was bunking the class.This intriguing question originated from Perl DBI Overview in section MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

Right answer is (a) $rc

Explanation: The PERL Non-handle variable ‘$rc’ returns code from operations that RETURN TRUE or FALSE. ‘$rv’ returns value from operations that return an integer. ‘$rows’ returns value from operations that return a row count.
Discussion
56.

The variable that is a handle to a database object is ______________(a) $dbh(b) $sth(c) $fh(d) $hThis question was posed to me in an online interview.This interesting question is from Perl DBI Overview topic in division MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

Correct choice is (a) $dbh

For EXPLANATION I would say: The variable NAMED ‘$dbh’ is a HANDLE to an open file. ‘$h’ is a generic handle and the meaning depends on context. ‘$dbh’ is a handle to a DATABASE object. ‘$sth’ is a handle to a query object.
Discussion
57.

Which variable is used as a handle to an open file?(a) $dbh(b) $sth(c) $fh(d) $hI got this question in semester exam.The doubt is from Perl DBI Overview topic in division MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

Right choice is (c) $fh

Easiest explanation: The variable named ‘$fh’ is a handle to an open FILE. ‘$h’ is a generic handle and the meaning depends on context. ‘$DBH’ is a handle to a database OBJECT. ‘$sth’ is a handle to a QUERY object.
Discussion
58.

In Perl DBI, functions are called ______________(a) functions(b) procedures(c) methods(d) programsThis question was addressed to me in quiz.My question comes from Perl DBI Overview topic in portion MySQL Programs Using Perl DBI and PHP of MySQL

Answer» RIGHT choice is (c) methods

The explanation is: In the DBI API, functions are called and POINTERS to STRUCTURES are used. The functions are called ‘methods’, pointers are called ‘references’, POINTER VARIABLES are called ‘handles’.
Discussion
59.

Issuing ‘SELECT’ on a MERGE table is like _____________(a) UNION(b) UNION ALL(c) UNION DISTINCT(d) JOINThis question was posed to me in an online quiz.My question is taken from Perl Script Characteristics topic in section MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

The correct answer is (b) UNION ALL

Easiest EXPLANATION: Performing a ‘SELECT’ operation on a ‘MERGE’ table is like performing ‘UNION ALL’. This means that DUPLICATE ROW results are not removed. ‘SELECT DISTINCT’ is like ‘UNION’ or ‘UNION DISTINCT’.
Discussion
60.

To combine multiple retrievals, which keyword is used to write several SELECT statements between them?(a) COMBINE(b) CONCAT(c) JOIN(d) UNIONThe question was asked during an internship interview.My doubt is from Perl Script Characteristics topic in chapter MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

Correct option is (d) UNION

Best explanation: The ‘UNION’ operator is used for combining the results of various ‘SELECT’ queries into ONE. For EXAMPLE, ‘SELECT a FROM table1 UNION SELECT a FROM table2;’ produces the results from tables table1 concatenated with that of table2.
Discussion
61.

Which of these operators does not perform relative value comparisons?(a) =(b) ==(c) =The question was posed to me during an online exam.My enquiry is from Perl Script Characteristics in portion MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

The correct option is (B) ==

EXPLANATION: The operators =, <>, >, >=, <, and >= perform relative VALUE comparisons in MySQL. ‘==’ is not a valid comparison operator in MySQL. Such operators are useful in FILTERING INFORMATION from a table.
Discussion
62.

What is the facility that allows nesting one select statement into another?(a) nesting(b) binding(c) subquerying(d) encapsulatingI had been asked this question during an interview for a job.This interesting question is from Perl Script Characteristics in section MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

The correct choice is (C) subquerying

Best explanation: The ‘subquerying’ support provided by MySQL is a capability that ALLOWS writing one ‘SELECT’ statement within PARENTHESES and NESTING within ANOTHER. This allows logically selecting content from tables.
Discussion
63.

Which is the join in which all the rows from the right table appear in the output irrespective of the content of the other table?(a) CARTESIAN JOIN(b) CROSS JOIN(c) INNER JOIN(d) RIGHT JOINThis question was addressed to me during a job interview.I would like to ask this question from Perl Script Characteristics in chapter MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

The correct OPTION is (d) RIGHT JOIN

The explanation: In a ‘RIGHT JOIN’, the OUTPUT is produced for every ROW of the right table, even if it does not EXIST in the other table. This is the reason why it is CALLED a ‘RIGHT JOIN’. ‘RIGHT JOIN’ and ‘LEFT JOIN’ are a kind of OUTER JOIN.
Discussion
64.

The default path to perl in Unix is ______________(a) /usr/bin/perl(b) /usr/bin(c) /usr/perl(d) /usr/perl/binThe question was asked in an international level competition.The origin of the question is Perl Script Characteristics in portion MySQL Programs Using Perl DBI and PHP of MySQL

Answer» CORRECT answer is (a) /usr/bin/perl

For explanation I would say: All Perl SCRIPTS generally begin with a #! (shebang) line. A SCRIPT is a FILE containing a sequence of commands. The Perl scripts are TEXT files, which can be ceated using any text editor.
Discussion
65.

The Perl DBI is ______________(a) database inheritance(b) database integrity(c) database interface(d) database isolationI had been asked this question by my college professor while I was bunking the class.My doubt stems from Perl Script Characteristics in section MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

Correct OPTION is (c) database interface

To ELABORATE: The Perl DBI is the Perl Database Interface. The work of the interface is to form a LINK between the application PROGRAMMING interface in C with all the other programming languages.
Discussion
66.

The shebang line is ______________(a) #!(b) !#(c) #$(d) $#I got this question in an online interview.I'd like to ask this question from Perl Script Characteristics in division MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

The correct choice is (a) #!

Easiest EXPLANATION: The PERL scripts are text files, which can be ceated using any text editor. All Perl scripts generally begin with a #! (shebang) line. A script is a FILE CONTAINING a sequence of commands.
Discussion
67.

Perl scripts are text files.(a) True(b) FalseThis question was posed to me in examination.This is a very interesting question from Perl Script Characteristics topic in chapter MySQL Programs Using Perl DBI and PHP of MySQL

Answer»

The CORRECT ANSWER is (a) True

Best explanation: The Perl SCRIPTS are text files, which can be ceated using any text editor. All Perl scripts generally begin with a #! (shebang) line. A script is a file CONTAINING a SEQUENCE of commands.
Discussion