What is three-tier architecture

What is three-tier architecture?

The three tier software architecture (also known as three layer architectures) emerged in the 1990s to overcome the limitations of the two tier architecture. This architecture has aggressively customized and adopted by modern day system designer to web systems.

Three-tier is a client-server architecture in which the user interface, functional process logic, data storage and data access are developed and maintained as independent modules, some time on separate platforms. The term "three-tier" or "three-layer", as well as the concept of multi-tier architectures (often refers to as three-tier architecture), seems to have originated within Rational Software.

The 3-Tier architecture has the following three tiers.

1. Presentation Tier or Web Server: User Interface, displaying/ accepting data/ input to/ from the user
2. Application Logic/ Business Logic/ Transaction Tier or Application Server: Data validation, acceptability check before being added to the database and all other business/ application specific operations
3. Data Tier or Database server: Simple reading and writing method to database or any other storage, connection, command, stored procedures etc