ASP NET and the Three-Tier Architecture - Assignment Example

ASP .NET and the Three Tier Architecture Section 1: ASP .NET (Active Server Pages in the dotNet framework) is one of the major technologies that can be used to develop dynamic pages for websites. This technology is superior to the client – server architecture and provides flexible ways to present and process information in the websites. It is a code behind model similar to that of its predecessor ASP (Active Server Pages). The web pages developed in .net have the extension of ‘.aspx’. Though the web browser does not require any framework to be installed, the web server which is executing the requests, need to have the .Net framework installed for the ASP .NET pages to work. Three - Tier Architecture: ASP .NET functions on a three – tier architecture. The three tiers or the layers are the presentation or the application layer, the business layer and the data layer. The three layers separate the various functionalities and enable the development process to be simpler and highly reusable. Presentation Layer: The presentation layer is basically the front end of the website, i.e., the pages and forms that are visible to the end user. They are composed of both static and dynamic content. The presentation layer is the front end and hence care has to be taken to make it user friendly and easily accessible to the user. The presentation layer gets sends queries to the business layer and receives information. However, the presentation layer is never connected to the data layer directly. In the case of the ecommerce site, the presentation layer is the shopping cart and the catalogue presented to the user. Business Layer: As discussed, the presentation layer sends the request for dynamic content to the business layer. The business layer acts as a mediator between the presentation layer and the data layer. It also has the business logic to process the data. The request is sent to the data layer and the data received is sent back to the presentation layer. The business layer also validates the input from the user before sending the request to the data layer. For instance, when the user selects a page for a particular product, the presentation layer sends the request to the business layer. The business layer then identifies other attributes, such as the product category, product code, etc.., and sends it to the data layer. It is advantageous to include as much logic as possible in the business layer itself, so that it is easier to maintain and change the logic whenever required. Data Layer: The data layer serves the data from the database. This layer accesses the database using stored procedures or inline queries. The sole purpose of this layer is to retrieve data and hence, it is possible to logically use the same data for various functions of the application, i.e., one data layer can serve many calls from the business layer. For instance, the business layer can send a request for product details by sending the product code. The data layer then executes the query or procedure and obtains the data related to the product, and then sent to the business layer. Advantages: There are many advantages of using this three – tier architecture. The main expectation from a technology is its ease of use. It should also be easy and simpler to maintain the website using the technology. The website might expand in the future and the website should be able to accommodate this increase in size, in terms of data and users. ASP .NET is an excellent solution which caters to these requirements and these are discussed in the sections below. Ease of Use: The main advantage of ASP .NET is its ease of use. Applications developed using the ASP .NET perform well as event driven applications. i.e., the application executes based on user actions also called as events. There is an extensive collection of controls and class libraries. These allow rapid application development, as many common functions and web controls are already included in the framework. Most of the editors also visually show the controls and it makes it simpler to complete the tasks. The source code and the template are separate and thus a developer can focus on getting the template while another can work on the source code and it can be integrated easily. User defined controls can also be developed and used throughout the site. The controls can be included in any page by just calling the user control. This will save repetition of code and effective reusability. As the data layer is separate, any modifications in the fieldnames can be handled effectively by just modifying the procedure or the query. Efficient Maintenance: Websites developed using the ASP .NET framework can be effectively maintained. As the applications are built on a three tier architecture, it is very simple to debug and make simple changes. Any change in the design or the presentation of the website can be edited and modified without affecting its functionality as the presentation is maintained in a separate layer. Similarly, any changes in the business logic can be implemented in the source code and the changes will be effected across all the pages of the presentation layer. As the class files that have the business logic are reused across many pages, any modification in the business function will be effected immediately in the presentation layer. As the input to the data layer is validated by the business layer, the errors that can be returned from the database are limited and easier to handle, unlike the client – server architecture. For instance, the products in the ecommerce site can be edited and more categories can be included. A single product can come under many categories and these are easier to maintain and edit using the business layer. As the pages are populated based on user controlled events, more options can be added for the user to select. This will enable a more interactive product catalogue. Scalability and Performance: As the business grows, the traffic to the site will also increase and the amount of data and the products handled will also increase. Hence the technology used should be able to provide high quality performance under all circumstances and the application should be scalable. ASP .NET provides a number of functions to maintain the performance and overcome the scalability issues. There are a number of functions which are in-built and also can be built manually to maintain performance under multiple requests to the server. There are a number of facilities to avoid unnecessary requests to the server and manage the traffic effectively. The server side coding is compiled to dll files on the web server. This indicates that the technology has the performance benefit due to the code being accessed from the pre compiled binary files. Also, the page caching option in the browser can reduce the download times for the websites to a great extent for repeat visitors. Summary: The development will take lesser time due to the vast library of in built controls and maintenance of the site will also be simpler due to the reusability of the code. In the long term, ASP .NET will be the best technology to support a completely data based application with heavy traffic to the website. It is evident from the above discussions that ASP .NET will be the best suited platform for developing the ecommerce website for the company. Section 2 – Styling and Themes: ASP .NET has a ‘Themes and Skins’ feature which enables the user to store style and layout information in separate groups of files called Themes. These themes can then be applied to the entire website. Any modifications and changes in the styles can be easily managed by editing the theme files and all the pages using the theme will reflect the changes. This removes the need to manually change the styles for all the pages to make them consistent. Development: There are a number of pre-built themes that can be used. Users can also manually develop themes and apply to the server controls. The main object models supported by controls are the stylistic properties such as the font, background colour, etc., and the cascading style sheets (CSS). They can be entered as a theme and used throughout or a part the site. The themes are a group of files including the skin information and the css files. Individual controls are specified as a skin ion a theme. The cascading style sheets carry the information of the properties of the content of the website. Many themes can be included in a website and the themes can be applied to different pages of the site as needed. The custom built themes are stored in the “App_Themes" folder inside ASP.NET applications making them easier to manage and interpolate according to the requirements. Advantages: There are a number of advantages of using themes while developing websites using the ASP .NET technology. The design elements of the site are implemented using various style attributes. It is very essential that the styles used throughout the website are consistent and there are no erroneous differences. This can be applied by using themes. Hence uniform design elements are used throughout the site. Also, many themes can be created, based on different colour schemes and attributes and applied to pages depending on the functionalities. One most important advantage of using themes is the ease to maintain the website design. When there is a need to change any design attribute, it is not necessary to do so manually for all the pages. Modifying the theme will implement the changes in all the pages which use it. The themes can also be reused effectively by modifying certain elements to create new versions. The themes can also be modified programmatically, by changing the name of the theme to be used based on user events. Thus themes can also be used to give the liberty to the user to select the style for viewing the website. This indicates that ‘themes’ form a very useful element of ASP .NET and can be effectively used to manage the design element and the look and feel of the website. Read More