PHP:
PHP is a widely-used general-purpose scripting language that is especially suited for
Web development and can be embedded into HTML.
[17] PHP generally runs on a
web server, taking PHP code as its input and creating Web pages as output. However, it can also be used for
command-line scripting and
client-side GUI applications. PHP can be deployed on most
web servers and on almost every
operating system and
platform free of charge. The PHP Group also provides the complete source code for users to build, customize and extend for their own use.
PHP primarily acts as a
filter.
[18] The PHP program takes input from a file or stream containing text and special PHP instructions and outputs another stream of data for display.
From PHP 4, the PHP parser
compiles input to produce
bytecode for processing by the
Zend Engine, giving improved performance over its
interpreter predecessor.
[19] PHP 5 uses the Zend Engine II.
MySQL:
MySQL is popular for
web applications and acts as the database component of the
LAMP, MAMP, and WAMP platforms (Linux/Mac/Windows-Apache-MySQL-PHP/Perl/Python), and for open-source bug tracking tools like
Bugzilla. Its popularity for use with web applications is closely tied to the popularity of
PHP and
Ruby on Rails, which are often combined with MySQL.
PHP and MySQL are essential components for running popular
content management systems such as
Joomla!,
e107,
WordPress, and
Drupal.
Wikipedia runs on
MediaWiki software, which is written in PHP and uses a MySQL database.