Designing the Three-Tier CML Application

The Corporate Media Library (CML) application is designed to have three logical layers, or tiers. These are:

• CML User-Services Tier. The CML application is designed for a browser user interface. The user services are performed by the browser client and a Web server. The Web server is responsible for formatting the pages the user sees. The browser is responsible for displaying the pages and downloading additional code the pages may need. The application can be accessed using any browser that supports client-side VBScript, dynamic HTML, and client-side ActiveX® controls.
• CML Business-Services Tier. The business logic of the CML application is executed in this layer. The business logic is implemented through components that run on the server. The components call stored procedures that reside in the SQL Server™ database and execute code that creates HTML pages.
• CML Data-Services Tier. The CML SQL Server database and the Fitch & Mather Corporation's Microsoft® Exchange Server directory reside in this layer.