You have been selected to find the best client-server computing architecture for a Web-based order entry system that is being developed for L. L. Bean. Write a short memo that describes to the project manager your reason for selecting an n-tiered architecture over a two-tiered architecture. In the memo, give some idea as to what different components of the architecture you would include.

The N-tier architecture helps to manage all the components (business layer, presentation layer, and database layer) of an application under one roof.

Explanation:

n-tier client/server architecture logically separates the user interface, database, and procedural code (business logic) into

at least three separate tiers. The business logic resides in the middle tier and may run on one or more servers. The user

interface interacts with the middle-tier by remotely invoking procedures and receiving results. The concept is similar to

the use of database procedures except the middle tier procedures are not limited to the proprietary SQL of an RDBMS.

In addition, the interface, database, and business logic are often physically distributed to run on many different machines. When an n-tier application is distributed effectively, system resources are more efficiently used and applications have better performance.

N-tier client/server is able to scale to thousands of users because it does not have the one-client, one-connection requirement of two-tier client/server.

N-tier client/server applications use middleware to funnel client connections to the database server.

N-tier client/server provides many benefits when working with relational databases. Clients connect to the middle tier

instead of the database; thus shielding the client application developer from the complexity of the database structure. In

addition, by placing the SQL code inside server processes, the client application is shielded from database changes. When changes are made to the database, the middle-tier server process must be modified, but the client applications can remain unaffected. If several client applications share the same server process, the change only needs to be made in one place.

N-tier/client server has been used to create complex applications that would be difficult, if not impossible, to create using a two-tier approach.