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Web Application - Patterns

n-Tier Arquitecture

Break the system into different pieces or tiers that can be physically separated:
  • Each tier is responsible for providing a specific functionality
  • A tier only interacts with the tiers adjacent, to it through a well-defined interface

Advantages 

  • Manages complexity of the design
  • Create a balance between innovation and standardization
  • Systems are much easier to build, maintain, scale and upgrade

3-Tier Architecture

  1. Presentation tier:  User interface and subdivided into two tiers:
    1. Client tier: client-side user interface components
    2. Presentation logic tier: server-side scripts for generating web pages
  2. Application (logic) tier :  Retrieves, modifies, delete data in the data tier and sends the results to presentation tier. Also process the data itself and is subdivided into two pieces
    1. Business logic tier: Models the business objects associated with the application and captures the business rules and workflows associated with how these processes can be processed and manipulated
    2. Data access tier:  Responsible for accessing data and passing it to the business logic tier
  3. Data tier:  Source of the data associated with the application


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