PHP Interview Questions and Answers
PHP earlier stood for Personal Home Pages, but now it stands for Hypertext Pre-processor. PHP is a server-side scripting language that is used for building web pages and applications. We have just added more questions in our question bank for PHP interview questions. This language includes many Frameworks and CMS for creating large websites. Even a non-technical person can create web pages or apps using PHP CMS or frameworks. PHP supports various frameworks and CMS that are used to develop applications.
Before getting confused with the plethora of PHP developer interview questions, you need to ensure the basics. This question will help you to understand the core basics of PHP and make you even more confident enough to jump onto the advanced questions.
| Quick Facts About PHP | |
|---|---|
| What is the latest version of PHP? | 8.0.3, released on 4th March 2021 |
| Who is the developer of PHP? | Rasmus Lerdorf |
| What language does PHP use? | C language |
| PHP License | It is a BSD-style license which does not have the "copyleft" and restrictions associated with GPL. |
- It runs on various platforms, including Windows, Mac OS X, Linux, Unix, etc.
- It is compatible with almost all servers, including Apache and IIS.
- It supports many databases like MySQL, MongoDB, etc
- It is free, easy to learn and runs on the server-side.
- PHP can operate various file operations on the server
Note: This is a list of the most frequently asked PHP interview questions. Please have a good read and if you want to download it, it is available in a PDF format so that you can brush up your theoretical skills on this subject.
Top PHP Developer Interview Questions
| GROUP BY | ORDER BY |
|---|---|
| Used for aggregating data in a database. | Used for sorting data in a database. |
| Used to change the form and composition of Data | Used to change the display mode of data. |
| Attributes within GROUP BY are similar | Attributes within ORDER BY are not similar. |
| Its function is to calculate aggregates. | Its function is to sort and arrange in columns. |
In PHP, both setters and getters are methods used by developers to obtain or declare variables, especially the private ones.
Why are they important?
They are crucial because these methods allow for a certain location which will be able to handle before declaring it or while reverting it back to the developers.
The default session time in PHP is 1440 seconds or 24 minutes. The default session path is a temporary folder/tmp.
There are two ways to increase the maximum execution time of a script in PHP available as following.
Method 1: Update php.ini file
To complete this process, we have to open the php.ini file and rearrange the max_execution_time (in seconds) as per our desired time.
Syntax
max_execution_time = 180 //180 seconds = 3 minutes
Method 2: Update .htaccess file
php_value max_execution_time 300
Method 3: Update your .php file
Here, we have to place the below-mentioned syntax on top of the PHP script.
ini_set('max_execution_time', 300);
ini_set('max_execution_time', 0);
In PHP, Design patterns are technically a description of communication between objects and classes which are customized in order to solve a common obstacle related to designs in a particular context. Basically, they provide a common reusable solution to everyday programming problems. Design patterns or templates help in speeding up the process of web development and can be used multiple times in different scenarios as required.
| Constant | Variables |
|---|---|
| In PHP, the constant is an identifier or a name for a simple value. The constant value can't be changed during script execution. | In PHP, the variable is a name or symbol which stands for value and used to store values such as characters, numeric, character string and memory addresses. |
| No dollar sign ($) is required before using a constant. | Variables require a dollar sign ($) to be executed. |
| It can't be defined by simple assignment. Only define() function can define it. | It is possible to define a variable by simple assignment. |
| It can be redefined or undefined after it gets set. | We can redefine or undefine after it gets set. |
| define('TITLE', 'Best Interview Question') | $title = 'Best Interview Question' |
Cross-Site Scripting (XSS) is one of the most common and dangerous security vulnerabilities existing within web applications. It is a means to gain unauthorized access by attacking PHP scripts present in your web app.
In PHP, developers use the break statement to terminate a block and gain control out of the loop or switch, whereas the continue statement will not terminate the loop but promotes the loop to go to the next iteration. The break statement can be implemented in both loop (for, while do) and switch statement, but the continue statement can be only implemented in the loop (for, while do) statements.
In PHP, an abstract class is one in which there is at least one abstract method. An abstract method is one that is declared as a method but not implemented in the code as the same.
abstract class ParentClass {
abstract public function someMethod1();
abstract public function someMethod2($name, $color);
abstract public function someMethod3() : string;
}
Top 10 PHP Interview Questions
Here you will find the list of Top PHP interview questions, which were written under the supervision of industry experts. These are the most common questions and usually asked in every interview for the role of the PHP Developers.
- What are Design Patterns in PHP?
- What is the difference between abstract class & interface in PHP.
- What is traits & how it can we used?
- What is the use of .htaccess file?
- What is the difference between MyISAM and InnoDB?
- What is the difference between Public Private and Protected?
- What is Constructor and Destructor?
- What is final class and final method in PHP?
- What is a static member function?
- What is function Overloading and Overriding in PHP?