Are you looking for a job as a PHP developer? Do you want to ace the PHP interview questions and land your dream job? If yes, then this blog post is for you. In this post, you will find a comprehensive list of the most common and important PHP interview questions, along with detailed answers and explanations.
You will also learn how to prepare for the interview, what to expect from the interviewer, and how to showcase your skills and experience. Whether you are a beginner or an expert, this blog post will help you boost your confidence and impress your interviewer. So, what are you waiting for? Read on and get ready to rock the PHP interview questions.
PHP Interview Questions for Freshers
The most typical PHP interview questions for new hires and seasoned professionals in the field are covered in this post.
1. Distinction between variables and constants in PHP?
In PHP, variables, and constants differ in the following ways:
Constants and Variables
- A variable’s value may change while the program is running.
- While a script is running, the constant value cannot be changed.
- The $ sign must always be at the beginning when using a variable.
- A dollar sign ($) is not required before a constant.
- A variable can be defined using a simple assignment.
- To define constants, more than simple assignments are required. They are determined using the define() function.
- The default access scope is currently being used.
- Constants can be accessed at any point in the scope.
2. What is the definition of a PHP session?
A session in PHP is a way to save information that can be used on multiple pages of a website. Unlike cookies, the information is not stored on the user’s machine. The session will create a file in the server’s temporary directory that holds the values of the registered session variables. During that visit, this information will be available on every website page.
When you use an app, you open it, make necessary changes, and close it. This appears to be a session. The computer recognizes you. It can tell when you open and close an app.
However, because an HTTP address does not keep a state, the webserver does not know who you are or what you do for a living on the internet. Session variables save user data to be used on multiple pages (e.g., username, favorite color, etc.).
Session variables, by default, persist even after the user closes the browser.
Session variables store information about a single user and are visible on all pages of a single application.
3. What does the acronym “PEAR” stand for?
PEAR is an acronym for “PHP Extension and Application Repository.” The PEAR framework and repository contain all the PHP parts that can be reused.
PEAR assists web developers in developing more advanced programming skills. It contains several PHP libraries and code fragments. You can also use the command-line interface to install packages automatically.
4.Does PHP take the case into account?
PHP is a case-sensitive programming language. Variable names are case-sensitive, whereas function names are not. Furthermore, while the rest of the speech concerns capitalization, user-defined functions are not.
In PHP, for example, user-defined functions can be written in lowercase but called with uppercase names, and everything will still work correctly.
5.How many different types of PHP variables?
- Variables in PHP are made up of one of eight different types of data. Here’s how it’s done:
- Integers are whole numbers without a floating point. Ex: 1253.
- Doubles are numbers that have a floating point. Ex: 7.876
- Booleans represent the true and false states of logic.
- NULL is the only value that can be assigned to the particular type NULL. When a variable does not have a value, NULL can be set.
- Arrays: An array is a named, ordered list of data of a specific type. $ colors = array(“red,” “yellow,” “blue,” etc.
- Strings of characters are formed. For instance, “Hey InterviewBit!
- Resources: Resources are unique variables that point to things not built into the PHP language (such as database connections).
- Objects represent a class, as well as its data and functions.
7. What are the rules for naming PHP variables?
When naming a PHP variable, you must adhere to two rules:
- A variable must have a name that begins with the letter $. For example, $price=100, where $price is the name of a variable.
- Variable names must begin with a letter or an underscore.
- Variable names can contain letters, numbers, or underscores. However, symbols such as +, -, %, &, and so on are not permitted.
- PHP variable names cannot contain any spaces.
- In PHP variables, case matters. As a result, $NAME and $name are treated as distinct variables.
PHP has the following flaws:
- PHP is not suitable for complex content-based web apps.
- It is not secure because it is open source, and ASCII text files are widely available.
- PHP does not allow you to change or modify how online apps work in their most basic forms.
- The performance of web apps will suffer if we use more PHP frameworks and tool features.
- PHP could be better at handling errors. PHP lacks the tools required to search for errors and warnings. It has fewer bug-fixing tools than other programming languages.
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Interview Questions for People Who Have Previous Experience
8.. How can HTML and PHP be combined?
PHP scripts can generate HTML, and PHP can read HTML data.
HTML is a client-side language, whereas PHP is a server-side language. When we run PHP on the server, the results are returned as strings, objects, and arrays, which we use to display the values in HTML.
This activity bridges gaps by utilizing the best aspects of both languages.
9.What does PHP’s @ function do?
@ is a PHP syntax used to conceal error messages. Any runtime errors that occur on lines that begin with the @ symbol will be handled by PHP.
10. What does PHP’s parser do?
A PHP parser is software that converts source code into computer-readable code. This means the parser converts our PHP code instructions into a machine-readable format.
To read PHP code, use the token get all() method in PHP.
11.Describe the various types of errors.
PHP errors are classified into three types:
- Notices: These are minor errors that may occur while the script runs. Users will not be able to see these. As an example, consider a variable that has yet to be set.
- Warning :A notice is less critical than a warning. The script will continue to run even if there are warnings. The user has access to these by default. An example would be to include() in a file that does not exist.
- Fatal : This is the most severe type of error; when it occurs, the script stops running. These are two examples: using need() on a non-existent file or attempting to access a non-existent object’s property.
12.What exactly are traits?
In PHP and other languages that do not support multiple inheritance, traits are a way to create code that can be used more than once. You cannot make it happen on your own.
A trait enables a developer to reuse groups of methods across multiple independent classes in different class hierarchies. This is intended to make single inheritance less constraining.
15.How does PHP’s “foreach” loop work?
The foreach statement is a PHP looping construct used to iterate and loop over array data types.
Foreach is simple to grasp. Pointers are increased, and values are assigned to elements with each value iteration. This operation is repeated until the end of the array is reached.
In PHP, the foreach statement is written as follows:
- The code foreach($array as $value) creates the loop.
16.What is the most common method for hashing a PHP password?
The crypt() function provides this feature, which offers many hashing algorithms. These algorithms include sha1, sha256, and md5, which are designed to work quickly and efficiently.
17.. What is the distinction between the include() and require() functions?
- This function copies the entire text of a file that has been called from another file into the file that has reached it.
- When a file is included but cannot be found, a warning (E-WARNING) is displayed, but the script continues to run.
- The functions include() and require() to perform the same functions. It also obtains the needed file and copies its contents into the file from which the require() method is invoked.
- If the included file cannot be found, the script will fail fatally (E COMPILE ERROR).
19. How do PHP cookies function?
A cookie is a small file the server leaves on the client’s computer. They save information about the user on the browser. When a user requests a specific page, a piece of code is installed on their computer that can be used to determine their identity. The cookie is also sent when a similar computer uses a program to request a page.
The session id generated on the back end is still stored in cookies after the user’s identity has been confirmed in encrypted form. It must be loaded into the computer’s browser. Because you can’t access objects, you can only store string values on a website or web app.
Cookies are typically associated with a specific URL. For example, Yahoo does not support Gmail cookies, and Gmail cookies do not help Yahoo. Cookies are, by definition, transient. A single website or web application can create up to 20 cookies. The cookie has a size that ranges from 50 bytes to 4096 bytes.
We can do the following with PHP’s setcookie() method:
setcookie(name, value, expiration date, path, secure, httponly, and domain)
In this case, you only need to know the name and nothing else.
The term “setcookie” is a good example (“instrument selected,” “guitar”).
20.What are the steps to create a new database using MySQL and PHP?
The 4 main steps used to create a new MySQL database in PHP are given below:
- A connection establishment is done to the MySQL server using the PHP script.
- The connection is validated. If the connection is successful, then you can write a sample query to verify.
- Queries that create the database are input and later stored into a string variable.
- Then, the created queries will be executed one after the other.
The tool of choice for creating dynamic web pages is PHP. It is not just for use by expert web developers. Non-technical users can also quickly pick up a few important tips to make their web sites more manageable and valuable.