ClientServer Architecture

Designing a Client/Server System

When building applications to solve business problems, you must consider the business requirements driving application development. At any point in the design process, the current state of the design should be directly traceable to the business problem and requirements.

Design Stages

The four client/server design stages, conceptual, logical, physical, and future are used to create optimized database systems. These stages progress from simple to complex design in order to provide a database implementation that accommodates your needs.

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Figure 6.6 The four design stages of creating a client/server database

Conceptual

During the conceptual design phase you should develop usage scenarios. These scenarios represent the user 's view of the solution to a specific business problem. A conceptual view places the emphasis on solving the business problem and deriving a solution that conforms to the needs and requirements of the users.

Logical

During logical design, you derive business objects and their related services directly from these usage scenarios. The logical view of the solution provides a basis for evaluating different physical options. It also formalizes the solution for the project team.

Physical

Physical design maps business objects and services to physical components. The components should be directly traceable to the originating business objects and through them to the usage scenarios. The physical design also focuses on leveraging existing infrastructure and technologies to minimize risk and to shorten development cycles.

Future

One or more usage scenarios for future (or proposed) extensions of the application or system are the foundation for all subsequent design activities. These usage scenarios embody the user's vision of the business solution and are as detailed as necessary to communicate this understanding. For each business activity, such as processing customer payments, a usage scenario will be developed. One scenario may describe how payments by check are processed, and another may describe how payments by credit card are processed .

Client Considerations

Users operating on a network may want to run the application from a network server. User applications should include a set of client components. This set consists of application components that are specific to the user, including local registry information and local files that provide the user with access to the server components.

Server Considerations

Server components should include the main executable files, DLLs, and any other files that need to be shared across the network. The server hardware is another consideration. For example, SQL Server provides support for Alpha AXP, MIPS, and Intel 32-bit x86-based microprocessors (such as the 80486 or the Pentium). Also, when there are a large number of clients you should install an ample amount of RAM to increase performance.


Microsoft Windows Architecture Training
Microsoft Windows Architecture for Developers Training Kit
ISBN: B00007FY9D
EAN: N/A
Year: 1998
Pages: 324

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