The user interface or the front end of the website with all the static and dynamic pages that are visible to the end user is the presentation layer. The presentation layer can be developed as soon as the design of the website has been finalized. The HTML (HyperText Markup Language) pages and the CSS (Cascading Style Sheets) are coded to develop the template for the front end (Ramirez, 2000). It is essential that this layer is user – friendly and has a simple and effective set of navigation rules. The presentation layer just displays the data to the end user and it never communicates directly with the database.
The business layer has the business logic for the website operations. It can also be said that the data for the dynamic sections of the template are rendered by the business layer and also the user inputs are validated and processed by the business layer. The business layer acts as a mediator between the data layer and the presentation layer (Mitchell, 2006). The business logic for the operation of the web application resides in the business layer. By having the entire business logic in a separate layer, it is every effective to modify the logic in this layer and the content gets modified in the presentation layer automatically at all necessary locations.
The data layer interacts with the database using stored procedures and queries to retrieve or store data in the database. The data is returned to the business layer which then processes the data and passes it on to the presentation layer accordingly. By separating the data layer, it is very simple to create functions (in this case, stored procedure) once and use them at all required places in the business layer. This reduces the code repetition to a great extent and also makes the code maintenance process very efficient.
It is clear that the various parts of the functions of a client – server architecture have