PHP Interview Question

-- What is PHP most used for?

PHP provides a variety of applications for developers. Some of the most commonly used PHP concepts are as follows:
With PHP, it is quite simple to grant restricted access to the website's needed material.
It enables users to access specific cookies and set them as needed.
Database manipulation activities such as insertion, deletion, and update are simple.
Form handling, along with file handling ideas and email integration, is commonly utilized.
The system module enables users to conduct a range of system operations such as open, read, write, and so on.

-- What is the distinction between include and require?

When need() fails to find a file, it raises a fatal error and terminates script execution, whereas include() generates a warning but continues execution.

-- What's the distinction between require_once(), require(), and include()?

require() includes and evaluates a specified file, whereas require_once() does so just once if it has not already been included (on the same page). As a result, require_once() is used when you don't want to include the file more than once on the same page.

-- What are the differences between the GET and POST methods?

We can transmit 1024 bytes using the GET method, while the POST technique may transport massive amounts of data. The GET method displays data in the URL, but the POST method does not.

-- What's the distinction between Session and Cookie?

Session data is saved on the server, whereas cookies are stored on the client machine. While the browser is open, we may specify an expiration date for a cookie, which will then expire.

-- How can we use PHP to extract data from the MySQL result set?

mysql_fetch_row
mysql_fetch_array
mysql_fetch_object
mysql_fetch_assoc

-- What does isset() do in PHP?

The isset() method is used to ensure that a variable is set and not NULL.

-- What is the distinction between mysql_connect and mysql_pconnect?

Mysql_pconnect() establishes a permanent connection to the database, which implies that the SQL link does not close after the execution of your script is over. Mysql_connect() is only used for new connections, whereas mysql_pconnect() first attempts to discover an existing connection with the same host. If a reference is found, it will be returned instead of initiating a new connection. After script execution, the connection to the SQL server is not ended by mysql_pconnect. Instead, the link will be preserved. Instead, the link will remain open for future use.

-- What are the distinctions between mysql_fetch_array(), mysql_fetch_row(), and mysql_fetch_object()?

mysql_fetch_array() returns results as an associative and numeric array.
mysql_fetch_row() returns values in the form of a numeric array.
mysql_fetch_assoc() returns values in the form of an associative array.
mysql_fetch_object: This function returns a result row as an object.

-- What's the distinction between echo and print?

The echo function is used to print a string. It can also contain several parameters. print is a construct that returns TRUE if the output is successful and FALSE if there is no output.

-- What exactly is PEAR stand for?

PEAR is an acronym that stands for PHP Extension and Application Repository. It enhances PHP and offers advanced programming to web developers.

-- How can we retrieve data given through URL using the GET or POST method?

The data on the PHP page may be received via the $_GET["var"] and $_POST["var"] arrays.

-- What exactly does the unlink() function do?

The unlink() method removes the file specified by the entry.