Crake a PHP interview questions and answers of part 1

 Dear All,

1.What is the difference between == and === in PHP?

== is a comparison operator that checks for equality of values, while === is a strict comparison operator that checks for equality of values and data types.

2.What is the difference between include() and require()?

include() and require() are both used to include files in PHP. The main difference is that require() will throw a fatal error if the file cannot be included, while include() will only throw a warning.

3.What is the use of the global keyword in PHP?

The global keyword is used to access variables that are defined outside the current scope, such as variables defined in a different function or in the global scope.

4.What is the use of the isset() function in PHP?

The isset() function is used to determine if a variable is set and is not null. It returns a boolean value (true or false).

5.What is the difference between echo and print in PHP?

Both echo and print are used to output strings in PHP. The main difference is that echo can output multiple strings at once, while print can only output one string and returns a value of 1.

6.What is a session in PHP?

A session is a way to store information about a user across multiple pages on a website. It allows you to store and retrieve user-specific data such as login credentials, preferences, and shopping cart contents.

7.What is the use of the $_POST variable in PHP?

The $_POST variable is an array that stores data submitted by a form using the HTTP POST method. It allows you to retrieve data from the form and use it in your PHP script.

8.What is the use of the $_SERVER variable in PHP?

The $_SERVER variable is a superglobal array that contains information about the current script and the server environment. It can be used to retrieve information such as the URL of the current page, the IP address of the user, and the user agent string.

9.What is the difference between a GET request and a POST request in PHP?

A GET request is used to retrieve data from the server, while a POST request is used to submit data to the server. GET requests are generally used for simple queries and do not involve changing the state of the server, while POST requests are used for more complex operations that involve changing the state of the server.

10.What is a PHP trait and how is it used?

A trait is a way to reuse code in PHP without using inheritance. It allows you to define a set of methods that can be included in multiple classes, without creating a hierarchy of classes. To use a trait, you simply include it in a class using the use keyword.

11.How do you prevent SQL injection attacks in PHP?

Answer: SQL injection attacks can be prevented by using prepared statements or parameterized queries with PDO or mysqli extensions in PHP. These methods will sanitize user input and ensure that malicious code cannot be injected into SQL statements.

12.What is the use of "final" keyword in PHP?

Answer: The "final" keyword in PHP is used to indicate that a class, method, or property cannot be extended or overridden by any child class. This provides an added layer of security and control over the code.

13.What is the difference between "private" and "protected" visibility in PHP?

Answer: "private" visibility in PHP restricts access to the property or method only within the class where it is defined, while "protected" visibility allows access to the property or method within the class as well as any child classes that extend it.

14.What is the difference between "session" and "cookie" in PHP?

Answer: "Session" is a server-side storage mechanism that allows PHP to store user-specific data that can be accessed across different pages and requests. "Cookie" is a client-side storage mechanism that stores data in the user's browser and can be used to remember user preferences or login information. Cookies can be set to expire after a certain amount of time, while sessions expire when the user closes their browser or after a certain amount of inactivity.

15.How do you debug PHP code?

Answer: PHP code can be debugged using a variety of tools, including PHP's built-in error reporting, Xdebug, or third-party debugging tools such as PhpStorm or Visual Studio Code. Debugging tools can help identify and fix errors in PHP code more efficiently by providing features such as breakpoints, step-by-step execution, and variable inspection.