Advantages: 3-Tier Architecture

• Heterogeneous systems

• • Tiers can be independently maintained, modified, and replaced

• Thin clients

• • Only presentation layer at clients (web browsers)

• Integrated data access

• • Several database systems can be handled transparently at the middle tier
  • Central management of connections

• Scalability

• • Replication at middle tier permits scalability of business logic

• Software development

• • Code for business logic is centralized
  • Interaction between tiers through well-defined APIs: Can reuse standard components at each tier