PHP Tutorial–Guest Book–System Definition and Requirements In this lesson I’m going to illustrate the system definition and requirements for the Guest Book application. It is an important step in developing any application, since this step gives us an orientation about the system and its functionality, what is expected from the system to do. actually the system definition comes from keywords from customers and end users, usually try to make it clear for what they need in the application, and what they expect the system to do. As developers it is our role to define the requirements for the system to be developed. In our example the system definition for the Guest Book is: A system that allows visitors of the site to post their comments and feedbacks about the site, with the possibility for managing comments and maintain it easily and user friendly. On the other hand, the system requirements are:
a web server, since it is clear that the developed system is going to run on the Internet, so it is a web-based application not windows-based. Database server, in order to store the posts inside and retrieve it easily and on time access. In our example am going to use MySQL server. Programming language, to apply the logic of the developed application and solve achieve the needed system. In our case, we are going to use PHP for this job, therefore the web server must be able to deploy PHP on it, so we might use Apache as server, we might use any server that supports PHP. For user interface, we need XHTML and CSS to provide a user friendly interface, moreover we might use some codes of JavaScript to maintain ease of use and validating user inputs.
We might look for the system as a 3-Tier Layer, the Data Tier (MySQL Server), the Middle Tier or Business Tier (Apache Server and PHP), and the Presentation tier (XHTML, CSS,…).
That’s all for aspects related to the system definition and requirements, our next lesson will focus on analysis and design for the database including the implementation for it. Until then wish you all enjoy the development steps for the Guest Book application, any questions or feedbacks don’t hesitate to share it with us. Cheers, Anas Jaghoub
