The Application Development Architectures

Based on the way, that you are implementing the presentation logic, business logic and database logic in your application, there are 4 development architectures.

1. One-Tier Architecture / Monolithic Architecture
2. Two-Tier Architecture
3. Three-Tier Architecture
4. Multi-Tier Architecture / Distributed Architecture

1) One-Tier Architecture:

• All types of logics (presentation logic, business logic and database logic) will be implemented directly within the form.
• That means there is no separation of presentation logic, business logic and database logic.
• This type of applications are not in the professional style.
• There is no re-usability of business code and database code.

2) Two-Tier Architecture:

• The Presentation Logic and Business Logics are maintained separately.
• The presentation logic is written in "Presentation Layer" and the business logic is written in "Business Layer" / "Business Access Layer".
• Note: Here, the database logic also can be written in the "Business Layer" only, even though it‘s not a good manner.

3) Three-Tier Architecture

• The Presentation Logic, Business Logic and Database Logics are maintained separately.
• This is recommended for the professional projects in the software companies.

4) N-Tier Architecture:

• In the 3-tier architecture, the "UI and presentation layer" will be located in the client system; and "business access layer and data access layer" will be maintained in the server system.
• Here, there is the requirement of a technology that allows us to connect "Business Layer" with "Presentation Layer". That technology is called as "Distributed Technology".
• The following are the well-known and important distributed technologies:
  
  1. DCOM (Distributed Component Object Model)
  2. .NET Remoting
  3. Web Services
  4. WCF (Windows Communication Foundation)

1. DCOM (Distributed Component Object Model)

• It is in usage, before .NET.
• It is platform dependent.

2. .NET Remoting

• It is introduced in .NET Framework.
• It is platform independent.
• It is suitable for the windows applications that run on LAN or intranet.
• It supports TCP and HTTP protocols.

3. Web Services

• It is available in ASP.NET.
• It is also platform independent.
• It is supported for web only.
• It is language independent (any .NET language).
• It is supported for ASP.NET web sites only.
• It supports SOAP and HTTP protocols.

4. WCF (Windows Communication Foundation)

• It is introduced in .NET 3.5.
• It is platform independent.
• It is language independent (any .NET language).
• It is supported for other language applications also (java applications, php applications etc.)
• It is supported for any type of network (LAN, intranet and internet also).
• It is supported in any type of applications (windows applications, web sites, WPF applications etc.)