PHP is a scripting language used for creating dynamic websites and mobile APIs. It can handle databases like MySQL and is often mixed with HTML. PHP is great for managing server sessions, handling changing content, and working with databases. It's perfect for building websites, like e-commerce sites, and is supported by most web hosting servers.
Review these PHP interview questions and answers for both beginners and experienced candidates to increase your chances of landing a PHP developer job. These questions are crafted to match what employers commonly ask during the hiring process.
PHP stands for PHP Hypertext Preprocessor. It is a scripting language that is used for web development. It is an open-source language that is embedded into HTML. When a server executes the code, then the client gets a generated HTML.
A PHP developer is a programmer who writes code at the server-side for web application logic. These programmers generally develop components that are supported at the back-end.
These developers connect the application with third-party web services and integrate the codes with the application to support the front-end web application logic.
PHP is used on all the widely used operating systems like Windows, macOS, Linux, etc. PHP has support for web servers that are available in the market.
The dynamic web page content is generated with this. It is mainly used for web development. Developers prefer to use this language to build server-side webpages and applications.
PHP was created by Rasmus Lerdorf, a Danish-Canadian developer, in 1994. All the new versions are produced by the PHP Group.
Big names like Etsy, Facebook, Pinterest, Tumblr, WordPress, Wikipedia, etc. are using PHP as the back-end language.
PEAR in PHP stands for PHP Extension and Application Repository. It is a repository and framework that is used for reusing the PHP components. PEAR enables the upgraded level of programming. It has various PHP libraries and code snippets. Moreover, it also contains a command-line interface for installing packages in PHP.
PHP traits are like reusable sets of code that can be used in different parts of a program. They're handy in languages that can't do multiple inheritances, and they help work around the limitations of inheritance in a program.
PHP is often not preferred for large content-focused web applications because it's considered less secure due to the widespread availability of its source code (open source). Additionally, the various features and tools in PHP can negatively impact the performance of applications. PHP is also criticized for its average ability to handle errors effectively.
WordPress, Joomla, Magento, and Drupal are some of the top Content Management Systems developed in PHP programming.
It is used when an immutable class like a string class is created. In PHP, classes and methods can be declared final, but properties can not be declared final. A final keyword indicates that the method can not be overridden by subclasses.
The unlink() function is used for handling the file system. It deletes the file that is given as an entry. Whereas, the unset() function is used for managing variables. It makes a variable undefined.
When both the sides have the same values or keys in the same order and have the same type, this type of operator is used.
PHP is a partial case-sensitive language. The variables in PHP are case-sensitive, and functions are not case-sensitive. User-defined functions in PHP are also not case-sensitive.
The echo in PHP can output one or more strings, and print can output only one. The echo is faster, and the print is slower.
A script is used to form a connection to the MySQL server. After verification of connection, it is checked by writing an example query. The queries are saved in a string variable, and then the constructed queries run.
The empty() function is used to check if a variable in a program has any value or not.
MIME (Multipurpose Internet Mail Extensions) in PHP is a standard used for identifying the type of data in a web response or email attachment. It helps define the format of data, enabling proper handling and rendering of content, such as images (image/jpeg), text (text/html), or multimedia (audio/mpeg).
The main update in PHP 5, not present in PHP 4, was the introduction of object-oriented programming (OOP) features. PHP 5 added support for classes and improved memory management, making it easier to create more organized and efficient code using OOP principles.
Variables in PHP can change their values during the program, while constants stay constant and don't change. Variables use a dollar sign ($), like $name, and their values can vary. Constants are defined using "define" and stay the same throughout the script, like define("PI", 3.14). So, variables can change, but constants remain fixed.
HTML and PHP work together to create dynamic web pages. HTML is used for structuring the content and layout of a web page, while PHP is a server-side scripting language that helps make web pages interactive by generating dynamic content. PHP can embed within HTML to create powerful, data-driven websites.
Errors in PHP are of 4 types.
A "foreach" loop in PHP is used to go through each item in a list (like an array) and perform actions on each item one by one.
The include() function is used to copy the content of a file called in the function. When the file can’t be found, it produces a warning.
The require() function works same as include() function. It takes the file and copies the data into a file. When the file can’t be found, it produces a fatal error.
session_start() is a PHP function used to begin or resume a user's session, which allows you to store data across multiple web pages. It creates a unique session ID for each user and initializes a storage area for session data.
session_destroy() is used to end a session, making all the stored session data inaccessible. It's like logging out, clearing all the session information, and preventing any further data from being saved in the session.
In PHP, you can concatenate (join together) two strings using the period (.) operator.
For example, if you have two strings, "Hello" and " world," you can concatenate them like this: "Hello" . " world." This will result in the string "Hello world."
The period (.) operator is used to combine text or characters from multiple strings into a single string, making it useful for building longer text or messages in PHP.
Overriding is pertinent to derived classes in PHP. When a parent class defines a method and the derived class needs to override that particular method, the concept of overriding takes place.
When functions have similar signatures but different parameters, the concept of defining functions takes place. This process is called overloading in PHP.
PHP Command Line Interface (CLI) is used to execute a PHP script. The command used for script execution is:
PHP script.php
GD library is used to execute PHP image functions. The imagetypes() is also used to find out the image type and format that is also supported by the latest version of GD-PHP.
The __wakeup method in PHP is used to retrieve the array of all the variables.
On the other hand, the __sleep method is used to return the array of all the variables. These both are used for functions that are needed for saving the arrays.
We can use the mysqli_affected_rows() function to return the total number of entries affected by an SQL query in PHP.
The array is of three types in PHP:
These are some of the most used PHP frameworks:
It is a library that is used to create the syntax tree of a source code. For this, the parser first passes the source code through a lexical analyzer, and then the syntax tree is formed.
The benefit of using a PHP parser is that it helps in analyzing static code. Programmers or web developers can check the code for syntax errors and meet quality criteria.
If you're familiar with PHP and have been working as a developer for a few years, you can use these PHP interview questions and answers for experienced professionals to assess your deep understanding of the language.
PDO stands for PHP Data Object. It is a PHP extension with a core PDO class and drivers that are database specific. PDO drivers can be accessed with the help of the PDO extension.
PHP PDO has a data-access abstraction layer. The function issues queries and fetches data without focusing on the database.
It is an attack to read the files of a web application. This attack is also called a dot-dot-slash (../) attack to climb to a higher-level directory. Path traversal in PHP is done to gain access to passwords and other sensitive information stored.
It is a library in PHP that is used for making HTTP requests from the server. The Client URL or cURL allows users to connect to a URL and retrieve data from the HTML page, header, and other data.
$message is a regular variable, and data stored in this is fixed.
Whereas, $$message is a reference variable, and data stored can be changed dynamically.
$message has a fixed name, and the value stores a fixed value, but $$message stores variable data.
Web servers are not designed to understand and parse PHP files. There are additional programs that are used to do that.
Here are some ways to execute PHP with Apache/ Nginx:
These files are used to make changes in PHP settings.
These files work when PHP is installed as Apache Module. A site can redirect a domain’s page to one page to HTTP or www.
When the type of the variable is changed on the basis of the assigned value, it is called type juggling in PHP.
The cookie is a small piece of information stored in the client browser used to recognize the user. When a client requests to the server on a site, the cookie is embedded with the request in PHP.
The setcookie() function is used to make cookies in PHP. This function is called before any script output generation in PHP.
It is a template engine that is written in PHP. Smarty will include variables and operators to allow adaptability in the particular templates. In PHP, Smarty is used to separate the concerns. It simplifies the program, which allows the front-end to change from its back-end.
A lambda function is used to store the data into the variables and then pass that data to arguments for the usage in various other functions and methods. This is also used to store data into variables. A user can see it as per the demand without defining it one more time.
Special tags <?= and ?> are used to display output directly to the browser.
It is a method in PHP to transform a single password into a string with a hashed password. This process can only be done one way, and the hashed passwords can not be moved to the original ones.
Hashing of passwords is done to improve the security of the program and the system. Some of the most used hashing algorithms in PHP are md5, bcrypt, sha1, and crypt.
It is an extension that is used to handle strings that are non-ASCII. It provides multibyte-specific string functions used for multibyte encoding. If there are more than 256 characters present in a byte-wise coding system, multibyte character encoding schemes are used.
Mbstring handles encoding based on Unicode like UCS2 and UTF8. It is used to handle character encoding conversion between encoding pairs. Moreover, it has an overloading feature to add multibyte to string functions. It also provides multibyte-specific string functions that detect the beginning or ending of the multibyte characters.
Both the functions are used to sort associative arrays in PHP.
The type hinting was introduced in PHP 5. It is used to specify the data type for function declaration in PHP like arrays, objects, etc.
When the function is not of a specified type, the run time will show an error, and the program will not be able to execute. It is used to organize the code better.
With the help of a .csv file and using a separator between fields, data can be exported into Excel files in PHP.
Here are some of the rules you must follow before naming variables in PHP:
The concept of OOPS is used in PHP language, and here are some of the commonly asked object-oriented programming PHP interview questions for you. You can prepare with these questions as these are the most asked questions on the concept of OOPS.
When functions are used to perform operations in a program, it is called procedural PHP programming language. When objects are created with data and functions, it is called OOPS in PHP.
A class in OOPS decides the behavior of an object, as well as what an object can contain. Using the class, the programmers can create specific objects.
The class is declared using the class keyword, along with the class name and curly braces.
The demand is on the rise for PHP developers as it is one of the most used languages. The regular updates in PHP are the main reason it won’t go out of demand.
If you are looking to build a career in PHP development, here is the list of top companies that are hiring PHP programmers and developers in India.
The average salary of a PHP Developer in India is INR 2.88 LPA. With experience and level of skills, the salary increases.
The salary of a PHP developer also depends on the company location. For instance, companies in Bangalore, Pune, Chennai, Mumbai, etc. offer higher packages compared to tier II and tier III cities.
In terms of career growth, this is a great field because the demand is increasing for this skill. You can also choose to become a freelance developer to get high-paying international projects.
Here are some of the most asked questions that are generally asked regarding PHP. It will clear your queries related to the PHP programming career.
The scope of PHP is very good as almost 80% of the websites use PHP as a development language. It is a decent career with constant growth that will land you in a pool full of opportunities as a developer.
Yes, PHP is still in demand, and it is not going out of demand anytime soon. The regular updates in PHP are one of the main reasons it will stay relevant in the near future as well in the sector of development.
You can purchase a PHP course from Arfi Technology and work on your skills. After the skill development, you can take the help of these interview questions to prepare for the interview. You can start a decent career in development in PHP after cracking the interview.
Here are some of the top skills that are required to become a PHP developer:
If you are working on becoming a full-stack developer, then knowledge of CSS, HTML, and JavaScript is also needed.
PHP is used to create dynamic content and interact with databases in a website. It is known for the simplicity of the code, flexibility, speed, etc.
It is not a tough language to learn. You can learn this language with ease if you know the basics of programming. Purchase an online course and learn complete PHP.
You can learn PHP in three to 8 months. It completely depends on the commitment. You can learn PHP from a course from Arfi Technology in 7 months.
