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Frequently Asked Questions - PHP
- What is PHP?
- What Is a Session?
- What is meant by PEAR in php?
- What are the differences between require and include, include_once?
- How can I execute a PHP script using command line?
- What are the differences between GET and POST methods in form submitting, give the case where we can use GET and we can use POST
PHP
The PHP Hypertext Preprocessor is a programming language that allows web developers to create dynamic content that interacts with databases. PHP is basically used for developing web based software applications.
A session is a logical object created by the PHP engine to allow you to preserve data across subsequent HTTP requests. There is only one session object available to your PHP scripts at any time. Data saved to the session by a script can be retrieved by the same script or another script when requested from the same visitor.Sessions are commonly used to store temporary data to allow multiple PHP pages to offer a complete functional transaction for the same visitor.
PEAR is the next revolution in PHP. This repository is bringing higher level programming to PHP. PEAR is a framework and distribution system for reusable PHP components. It eases installation by bringing an automated wizard, and packing the strength and experience of PHP users into a nicely organised OOP library. PEAR also provides a commandline interface that can be used to automatically install “packages”.
The include_once() statement includes and evaluates the specified file during the execution of the script. This is a behavior similar to the include() statement, with the only
difference being that if the code from a file has already been included, it will not be included again. The major difference between include() and require() is that in failure
include() produces a warning message whereas require() produces a fatal errors.
Just run the PHP CLI (Command Line Interface) program and provide the PHP script file name as the command line argument. For example, “php myScript.php”, assuming “php”is the command to invoke the CLI program.Be aware that if your PHP script was written for the Web CGI interface, it may notexecute properly in command line environment.
When you want to send short or small data, not containing ASCII characters, then you can use GET” Method. But for long data sending, say more then 100 character you can use POST method. Once most important difference is when you are sending the form with GET method.You can see the output which you are sending in the address bar. Whereas if you send the form with POST” method then user can not see that information.
