Php Interview Questions

We have covered PHP interview questions in an easy way so that any fresher or experienced developer gets information from these questions. we define each and every topic with an example so that any reader understand easily.

PHP stands for Hypertext Preprocessor. PHP is a server-side scripting language that is used to develop dynamic websites. Php is an open-source technology so you can free download through the internet.

php5 is upgrade version of php4 and php5 improved object orientated programming features.

There is four methods to retrieve the data in the result set of MySQL using PHP.
(i) mysql_fetch_row():- this function fetches one row from a result-set and returns it as an enumerated array.

(ii) mysql_fetch_array():- this function Fetch a result row as an associative array, a numeric array, or both.

(iii) mysql_fetch_assoc():- this function Fetch a result row as an associative array.

(iv) mysql_fetch_object():- this function Fetch a result row as an as an object.

This is very simple because we can use through javascript function.
[php]<script>
document.form.submit();
</script>
[/php]

Ans:- A session is a way to store information (in variables) to be used across multiple pages.
sessions are stored on the server.

Ans:- We can create session through session_start() function

Ans:- We set the value like this $_SESSION[$name]=$value;
Example:- [php]
<?php
$_SESSION[‘username’]=’John’;
?>
[/php]

Ans:- We can remove data through unset function.
Example:- [php]
<?php
unset($_SESSION[‘username’]);
?>
[/php]

Ans:- session_id() returns the session id for the current session.
Example:- [php]
<?php
session_id();
?>
[/php]

Ans:- We can change session id through session_regenerate_id(true) function.
Example:- [php]
<?php
session_regenerate_id(true);
?>
[/php]

Ans:- We can destroy all session data through session_destroy(void) or session_unset(void); function.
Example:- [php]
<?php
session_destroy();
or
session_unset();
?>
[/php]

Ans:- The default session time in php is until closing of browser.

Ans:- Cookies works on client side and it is stored on the user’s browser.

Ans:- A persistent cookie is permanently stored in a cookie file on the browser’s computer. By default, cookies are temporary and are erased if we close the browser.

Ans:- We can set cookie through setcookie($cookie_name,$cookie_value,$time) function.
Example:- [php]
<?php
setcookie("username", "John", time()+3600);
?>
[/php]

Ans:- We can retrieve cookie through $_COOKIE[$cookie_name].
Example:- [php]
<?php
echo $_COOKIE[‘username’]; //output:-John
?>
[/php]

Ans:- We can remove cookie through set the expiration date in the past.
Example:- [php]
<?php
setcookie("username", "", time()-3600);
?>
[/php]

$_SERVER is an array containing information such as headers, paths, and script locations.

Ans:- We can get through
[php]
$_SERVER[‘REMOTE_ADDR’]
[/php]

Ans:- We can get through
[php]
$_SERVER[‘HTTP_REFERER’]
[/php]

Ans:- We can get through
[php]
$_SERVER[‘HTTP_USER_AGENT’]
[/php]

Ans:- We can get through
[php]
$_SERVER[‘SERVER_NAME’]
[/php]

1) echo and print
2) include(), include_once(), require(), require_once()
3) print_r() and var_dump()
4) unlink() and unset()
5) GET and POST method
6) Split and Explode
7) array_merge() and array_combine()
8) urlencode and urldecode
9) $variable and $$variable
10) strstr() and stristr()