PHP Interview Question and Answers

PHP Interview Question and Answers for Freshers

 List out the 3 main differences between session and cookies

Sessions are stored in server which can hold multiple variables. Session expiry time is specified in configuration and remains active as long as browser is open. It is mainly used for login and logout purpose

Cookies are stored on user’s computer, those can be viewed in web browser options and cannot hold multiple variables. We have to set expiry time for each cookie. Sensitive information should not be stored in cookies.

How to redirect a page in php ?

header(“Location:index.php”);

 

How is isset() in php used ?

It is used to identify whether variable is set and is not NULL

 

How to get value for current session id?

 session_id()

 

What is meant by sql injection ?

sql injection is the most hacking techniques, it is the code injection that destroys your database by placing malicious code in sql statements via web page input.

 

What is Simple XML in php ?

It is an extension which allows us to manipulate easily and get XML data

 

What is php libxml ?

Libxml functions and constants used together with XSLT, SimpleXML and DOM functions. These functions require libxml package

 

What are the rules for naming a variable in php ?

Variables in php must start with a letter or underscore character, but cannot start with a number and can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ ) 

 

How will you link 2 strings in php ?

To link the 2 string variables use dot (.) or comma(,) operator

<?php

$string1=’’Good Morning’’;

$string2=’’1234’’;

echo $string1 . “ “ . $string2;

?>

Final output is 

Good Morning 1234

 

How to find the length of the string ’’Good Morning’’ ?

strlen() is the function which is used to find the length of the string

<?php

echo strlen (’’Good Morning!’’) ;

?>

And the output is 13

Variables including space and exclamatory mark has to be counted

 

How will you check if the file exists in php ?

file_exist()function

 

How is the session started in php ?

A php session is started by making a call to the session_start() function

 

How is the session destroyed in php ?

session_destroy()function

 

How do split function works ?

Split function divides a string into various elements, the elements are based on occurence of pattern in a string.

 

What is the fullform of PEAR and what is it?

PEAR - PHP Extension and Application Repository. It is a framework and distribution system reusable for php components and provides command line interface to install packages automatically.

 

What are the different data types in php?

There are 3 different types of data which are again subdivided into many types

Scalar type :

• Boolean
• Integer
• Float
• String 

Compound type :

• Array
• Object

Special type :

• Resource
• Null 

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