A sample customized web application architecture is as shown below –
As shown above, all the three tiers of the web server architecture, namely database server, business logic and presentation, are represented. The Apache web server, PHP engine, Database drivers and other utilities are closely compiled so as to improve speed and performance. The database server can be DB2 , Oracle, mySQL etc. PHP engine directly talks with DB via ODBC drivers. The business logic part consists of core PHP/PERL based programs that resides in lib or bin areas of the various web applications. Their main purpose is to control the flow and logic of the program. It is these programs that interacts with database and performs database transactions. The presentation part consists of PHP/HTML programs that display html content for user interaction.