PHP is a script language, which has a C-like syntax. Mostly it is used on web servers to deliever dynamic web pages. When requesting a file with a cerain file extension the web server will call a PHP interpreter. This interpreter executes the code that is defined in this file. As an example this could be a database selection, the result will be filled into the response of the web server.

In large applications PHP needs more ressources than for example JEE, but therefor when implementing code you get very fast results with PHP. There are also a lot of frameworks like Symfony which support the development process of an application.

With symfony there is a Model-View-Controller Framework, that is developed and maintained by the french company sensiolabs under the MIT license. It is free software. Its concepts are common to the Ruby on Rails framework, that is very in vogue during the last years. Symfony, the "Rails" for PHP supports the developer to easily and very fast create three tier web applications. Some of the wonderful features are:

• Database access through an integrated object-relational mapper
• Auto generation of create, update and delete interfaces, also known as Scaffolding
• Easy use of search engine optimized (SEO) URLs
• Internationalisation (I18N)
• Form validation
• Session handling
• Improvement of the performance by smart caching
• Excellent debugging capabilities