Component Design for Relational Databases - High-Performance Web Databases: Design, Development, and Deployment - page 386

Exhibit 25-2. Three-tier application architecture with data-mapping layer.
• Applications do not access the tables directly but use the interface
functions provided by the interface layer in C1.
• Satisfies an important OOD (object-oriented design) requirement:
keep function and data together.
• Eliminates redundant data access as well as data mapping.
• Separates the GUI from the business logic — an important require-
ment of three-tier client server computing.
• Allows implementation of n-tiered architecture since C1 can be de-
ployed on an application server.
• Provides much better change management (which as elaborated be-
fore, is an even greater benefit of object-oriented development than re-
use), since changes in the data model no longer affect client
applications directly. The only time the client applications are affected
is when changes to the data model/functionality affect the interface
between C1 and the client applications.
• Allows implementation of multiple interface or different views of data
thus adding a new twist to the classic MVC (Model View Controller)
object-oriented architecture.