For any application user is interacts with database. So in the two tier architecture it consists of clients and database. Here client tier is responsible for our business logic and user interface where as database tier is nothing but server tier is responsible for providing data to the client applications. But there are certain draw backs like it is little bit slow performance wise ,it will increase network traffic so Microsoft has introduced Windows Distributed internet Applications(Windows DNA) architecture this enables to implement three-tier architecture
In the three-tier architecture mainly it consists of following
It will have information about all the databases and tables .These services include ADO(ActiveX Data Object )and OLEDB it will allow to interact business logic with database
Business logic layer:
It is an intermediate layer between database and presentation mainly it we will place our business logic here means all the logical coding is placed here.
Presentation layer :
It is mainly used for display the data to the users. Main services of this are it support HTML,DHTML,Scripting languages and Win32 API.
1.Mainly we can improve performance of the application.
2.We can reduce the traffic flow between client and server
3.Security to our code.
4.It will support distributed environment.