Cognos 8 BI features a three-tierarchitecture, as illustrated in Figure 2.
Cognos 8 BI提供一个三层的体系结构，见图2。
2
Spring 2.5 adds two new annotations - @Service and @Controller - to complete the role designations for a common three-tierarchitecture (data access objects, services, and web controllers).
Traditional software developers generally build either a module within an application or a portion of a single layer in typical three-tierarchitecture.