Introduction

Multitier or ‘N-tier’ architecture is a software system segregated into separate sections (referred to as tiers or layers). The default set value of ‘N’ is three. It’s an architectural methodology incorporated as a part of web based software application development.

The need

There are many reasons of using such layers to construct an application. Here they go:

• Scalability: A layered structure provides an optimal amount of scalability to the system. Any of the tiers can be upgraded or interchanged independently without affecting the functioning of others.

• An ease in implementing changes: A software system is subject to changes. This change can come in the form of a functionality change, a functionality enhancement, a completely new module, or even a hardware infrastructure enhancement, and so on. In any case, changes can occur during the initial development or after the first version is complete. By designing a system architecture as multitiered from the very beginning, one can minimize the impact on the whole system when implementing any change to any layer.

• Maintenance ease: If the source code is organized into multiple tiers, debugging and application maintenance as a whole becomes easier. As a developer it is easy for you to locate specific sections where an error is occurring or a change is needed and do the needful. A well-structured architecture brings an easy solution to defects and bugs and allows easy upgrades or enhancements, which otherwise would be very much time consuming.

The description of individual layers

A typical multitiered application consists of:

• Entity Tier (your website application)
• Business Tier (the brain of your application)
• Data Tier (the data processing section of your application)

Entity Tier: This is the presentation logic layer, something that the users view. This includes simple control and user input validation, is similar to a web application. It is also known as ‘thin client.’ It has a reference of the business layer. This layer has no knowledge about the system working, database, or any information.

Business Tier: This is the ‘brain’ of your entire application. It provides the business processes logic and the data access. It will act as a bridge from the presentation to the data access so that the information can be processed in some cases and, in other cases, can simply be the conduit to ensure the smooth flow of information. This layer will have the most information about the activity and the processing that needs to take place and will have a heavy implementation of the business objects.

This layer does not know any information to access data. It just gives the requirement to the ‘data access layer.’ It sets forth the business rules from the earlier gathered requirements.

Data Tier: This is the only layer of your application that knows how to interact with the database servers and retrieve the required information. Without any knowledge as to who is asking or whom is it giving the information to, all what this layer does is that it gives information back to the request object.

Data retrieval process is most likely in the form of selecting, querying, inserting, updating, or deleting information to and from the database.

I hope this article has provided you a useful insight into the advantages of splitting an application into multiple layers. Have a great going!