Php Interview Questions With Answers 2022

PHP is a web language based on scripts that allows developers to dynamically create generated web pages.

Namely Php is a server side scripting language commonly used for web applications. PHP has many frameworks and cms for creating websites.Even a non technical person can create sites using its CMS.

WordPress, osCommerce are the famous CMS of php. Truly it is also an object oriented programming language like java, C-sharp etc. It is very easy for learning.

PHP means PHP: Hypertext Preprocessor.

PHP syntax resembles Perl and C.

PEAR means “PHP Extension and Application Repository”. It extends PHP and provides a higher level of programming for web developers.

Likewise PEAR is a code repository containing all kinds of php code snippets and libraries. PEAR also offers a command-line interface that can be used to automatically install “packages”.
$message vs. $$message in PHP

GET and POST are used to send information from client browser to web server. In case of GET the information is send via GET method in name/value pair and is URL encoded.

The default GET has a limit of 512 PHP INTERVIEW QUESTIONS 2 characters. The POST method transfers the information via HTTP Headers. The POST method does not have any restriction in data size to be sent. POST is used for sending data securely and ASCII and binary type’s data.

The $_REQUEST contains the content of both $_GET, $_POST and $_COOKIE.

There are 4 basically types of error.

Parse Error – Commonly caused due to syntax mistakes in codes e.g. missing semicolon, mismatch brackets.

Fatal Error – These are basically run time errors which are caused when you try to access what can’t be done. E.g. accessing a dead object, or trying to use a function that hasn’t been declared.

Warning Error – These occurs when u try to include a file that is not present, or delete a file that is not on the server. This will not halt the script; it will give the notice and continue with the next line of the script.

Notice Error – These errors occurs when u try to use a variable that hasn’t been declared, this will not halt the script, It will give the notice and continue with the next line of the script.

Session is a super global variable that preserve data across subsequent pages. Especially Session uniquely defines each user with a session ID, so it helps making customized web application where user tracking is needed.

Cookie is a small piece of information stored in client browser. It is a technique used to identify a user using the information stored in their browser (if already visited that website) . Specifically using PHP we can both set and get COOKIE.

index.php is the default name of the home page in php based sites.

The main difference between $message and $$message is that former one is a simple variable and later is a reference variable. $message is a variable with a fixed name and it consists of a fixed value. $$messages contains the variable itself.

We can send 1024 bytes using GET method but POST method can transfer large amount of data and POST is the secure method than GET method.

.htaccess files are configuration files of Apache Server which provide a way to make configuration changes on a per-directory basis. A file, containing one or more configuration directives, is placed in a particular document directory, and the directives apply to that directory, and all subdirectories thereof.

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Case Studio and Smart Draw.

It is possible to generate HTML through PHP scripts, and it is possible to pass information from HTML to PHP.

PHP and Javascript cannot directly interacts since PHP is a server side language and Javascript is a client side language. However we can exchange variables since PHP is able to generate Javascript code to be executed by the browser and it is possible to pass specific variables back to PHP via the URL.

URLencode returns a string in which all non-alphanumeric characters except -_. have been replaced with a percent (%) sign followed by two hex digits and spaces encoded as plus (+) signs.

It is encoded the same way that the posted data from a WWW form is encoded, that is the same way as in application/x-www-form-urlencoded media type. urldecode decodes any %## encoding in the given string.

unlink() deletes the given file from the file system. unset() makes a variable undefined.

Just run the PHP CLI (Command Line Interface) program and provide the PHP script file name as the command line argument.

The result set can be handled using mysql_fetch_array, mysql_fetch_assoc, mysql_fetch_object or mysql_fetch_row.

The strip_tags() function enables us to clean a string from the HTML tags.

ORM is Object Relation Mapper. ORM is programming technique for converting data between incompatible type systems in object-oriented programming languages.

Dispatching is the process of taking the request object, Zend_Controller_Request_Abstract, extracting the module, controller, action name, and optional parameters contained in it, and then instantiating a controller and calling an action of that controller.

In Zend Framework, bootstrapping is the process that loads your application. This includes, but is not limited to the Session.

Furthermore any resources needed by your application to process the request (the dispatch) to the application is bootstrapped/loaded/initialized before the request is fulfilled, e.g. before the controller delegates any input to the model and creates a response that is send back to the client.

New Relic is software as a service (SaaS) that monitors your Website and mobile applications(Android, iOS) in real-time that run in different environments like cloud, on-premise and hybrid.

Following are few benefits of New Relic:

1. Monitoring your website regularly.
2. Downtime Notification by email.
3. Custom Error recording and then report you in email & also can view in newrelic website.
4. Key Transaction tracking:
   You will be able to see where your application is spending most of its time (e.g. in the controller, model OR database).
5. External Service Call Recording (Webservices)

Apdex means Application Performance Index. It is standard method for reporting & comparing the performance of software.

Purpose: Analyse the performance, user satisfaction & expectation then Convert into percentage.

It is used to generate random numbers.If called without the arguments it returns a pseudo-random integer between 0 and getrandmax(). If you want a random number between 6 and 12 (inclusive), for example, use rand(6, 12).

This function does not generate cryptographically safe values, and should not be used for cryptographic uses. If you want a cryptographically secure value, consider using openssl_random_pseudo_bytes() instead.

Associative arrays are arrays that use string keys is called associative arrays.

SQL injection is a malicious code injection technique.It exploiting SQL vulnerabilities in Web applications.

Firstly, the the HTTP protocol specifies differing usages for the two methods. GET requests should always be idempotent on the server.

This means that whereas one GET request might (rarely) change some state on the Server, two or more identical requests will have no further effect.

Convert all applicable characters to HTML entities. This function is identical to htmlspecialchars() in all ways, except with htmlentities(), all characters which have HTML character entity equivalents are translated into these entities.

By using date_default_timezone_get and date_default_timezone_set function on PHP 5.1.0

date_default_timezone_set(’Asia/Tokyo’);
$stamp = mktime(8, 0, 0, 1, 1, 2000);
date_default_timezone_set(’US/Eastern’);
echo ‘
‘, date(DATE_RFC1123, $stamp) ,’
‘; ?>

:: is used to access static methods that do not require object initialization.

Yes, we use the urlencode() function to be able to protect special characters.

The SQL Server Driver for PHP v1.0 is designed to enable reliable, scalable integration with SQL Server for PHP applications deployed on the Windows platform.

Likewise the Driver for PHP is a PHP 5 extension that allows the reading and writing of SQL Server data from within PHP scripts. using MSSQL or ODBC modules we can access Microsoft SQL server.

CURL means Client URL Library. CURL allows you to connect and communicate to many different types of servers with many different types of protocols. libcurl currently supports the http, https, ftp, gopher, telnet, dict, file, and ldap protocols.

echo md5(uniqid(rand(), true));

There are two methods through which we can know the total number of elements:

sizeof($array_var)
count($array_var)

Split function splits string into array by regular expression. Explode splits a string into array by string.

The trim() function removes whitespaces or other predefined characters from both sides of a string.

strlen() function used to find the length of a string.

This function is used to determine if a variable is set and is not NULL.

It is used for sort an array by key in reverse order.

Unlink() deletes the given file from the file system.

It is used to print a data in the webpage, Example: <?php echo ‘Car insurance’; ?> , The following code print the text in the webpage.

We can include a file using “include() ” or “require()” function with file path as its parameter.

require() includes and evaluates a specific file, while require_once() does that only if it has not been included before (on the same page). So, require_once() is recommended to use when you want to include a file where you have a lot of functions for example.

This way you make sure you don’t include the file more times and you will not get the “function re-declared” error.

This is not actually a real function, It is a language construct. So you can use with out parentheses with its argument list.

Example
print(‘PHP Interview questions’);
print ‘Job Interview ‘);

in_array used to checks if a value exists in an arraY

count() is used to count all elements in an array, or something in an object.

The header() function sends a raw HTTP header to a client. We can use herder() function for redirection of pages. It is important to notice that header() must be called before any actual output is seen.

Sort(), arsort(), asort(), ksort(), natsort(), natcasesort(), sort(), usort(), array_multisort(), and uksort().

imagetypes() gives the image format and types supported by the current version of GD-PHP.

The mysql_fetch_object() function collects the first single matching record where mysql_fetch_array() collects all matching records from the table in an array.

CRYPT(), MD5()

unset($_SESSION[‘object’]);

$file=”full_path/filename.php” unlink($file);
//make sure you have enough permission to do delete the file.

$array = array(‘one’,’two’);
echo json_encode($array); //use json_decode for decode

parent::constructor()

Create session : session_start();
Set value into session : $_SESSION[‘USER_ID’]=1;
Remove data from a session : unset($_SESSION[‘USER_ID’];

We can connect Mysql Database with PHP using both Procedural and Object oriented style like below.

$link = mysqli_connect(“localhost”, “username”, “password”, “dbofpcds”);
$mysqli = new mysqli(“localhost”, “username”, “password”, “dbname”);
and in old type of connectivity were
$link = mysql_connect(“localhost”, “username”, “password”);
mysql_select_db(“database”,$link);

preg_match(“/^http:\/\/.+@(.+)$/”,”http://[email protected]”, $matches);
echo $matches[1];

In php.ini file:
set
short_open_tag=on
to make PHP support

By using $_SERVER[‘REMOTE_ADDR’],
$_SERVER[‘HTTP_REFERER’] etc.

AES_ENCRYPT () and AES_DECRYPT ()

By using
$_SERVER[’HTTP_USER_AGENT’] variable

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