What is three tier architecture?

The 3 tier software architecture was comes into action in the 1990s to overcome the limitations of the 2 tier architecture.

There are 3 layers when we describe about three tier architecture:-

1) User Interface (Client):- This interface is mostly the windows user interface or the Web interface but this has only the UI part.

2) Mid layer: - The Middle tier provides the process management where business logic and rules are executed and can accommodate hundreds of users (as compared to only 100 users with the 2 tier architecture) by providing functions such as database staging, application execution, and queuing.

3) Data Access Layer: - This is also known by the famous acronym "DAL" component. It has

Mostly the SQL statement which does the database operation section of the job.

The 3 tier architecture is used when an effective distributed server/client design is required that provides (when compared to the 2 tier) increased flexibility, performance, scalability, reusability, and maintainability, while hiding the complexity of distributed processing from the user.