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What is 3-tier Architecture

The 3-tier Architecture is all about separating the Business Logic from the Application and Data Storage. i.e., Database (in general). It is popularly called as MVC (Model-View-Controller) Model. User will interact with View part in the application. This will be controlled by Controller and Model layers.

Whenever user performs something, that will call some action handler in the Code behind and calls a functions in the Controller. In Object Oriented approach, Model consists of Business objects. Depending on the situation, some business object will be created and that will be used to store and retrieve data from the Database.

This separation is needed in real time application,
Because the change in one layer should not effect the other layer's functionality.

For Ex. Change in the Database from SQL server to Oracle is nowhere related to user. So he/she should not know these details while interacting with the system.

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