Introduction:
3-Tier architecture is a very well know buzz word in the world of software
development whether it web based or desktop based. In this article I am going to
show how to design a web application based on 3-tier architecture.
3-Tier architecture generally contains UI or Presentation Layer, Business Access
Layer (BAL) or Business Logic Layer and Data Access Layer (DAL) and sometimes
property layer.
Presentation Layer (UI)
Presentation layer contains pages like .aspx or windows form where data is
presented to the user or input is taken from the user.
Business Access Layer (BAL) or Business Logic Layer
BAL contains business logic, validations or calculations related with the data,
if needed. I will call it Business Access Layer in my demo.
Data Access Layer (DAL)
DAL contains methods that helps business layer to connect the data and perform
required action, might be returning data or manipulating data (insert, update,
delete etc). For this demo application, I have taken a very simple example. I am
assuming that I have to play with record of persons (First Name, Last Name, and
Age) and I will refer only these data throughout this article.
Property layer.
Generally it contains the entire variable those need to pass from presentation
to bal, bal to dal and vice versa so instead of writing those each and every
time we can create property layer.
Typical structure will look like this.
It contains one solution with three class library and one website.
![layer.gif]()
Now to create above structure first create new project and add one visual studio
blank solution.
Now add 3 class libraries and one website in it give the relative name to them.
For the code purpose or what to write in which layer please download the source
code.