The business-services tier is a collection of services that enforce business rules, process information, and manage transactions. It interacts with two tiers adjacent to it. The user-services tier for the Corporate Media Library/Literary Critique (CML/LitCrit) application is a client to the objects and services on the application's business-services tier. Similarly, business-services objects rely on the data-services tier to manage data processing by storing, retrieving, and manipulating data within the data stores.
Note Not all the business rules of this application are enforced on the Web server computer or the Microsoft Exchange Server computer; some are enforced at the client. For more information on the distribution of business logic over physical locations, see N-Tier Development Model.
This section discusses the parts of the CML/LitCrit application that perform business logic, regardless of their physical location.