Our goal is to develop a web based distributed n-tier application. Proposed Web based EPM will be based on Windows DNA model.

This document will highlight the design strategy for the n tiers of the architecture such as workflow layer design, middle-tier component design, migrating divergent user interfaces to consistent designs, and database access. It will also talk about the tools and technologies we are going to use.

Following are the various layers employed by most user interface–based, data processing applications:

A presentation, or user interface, layer with which the user interacts with the application. Workflow layer is implemented through a combination of ASP script, some client-side processing (depending on the client type), and a COM component. The Workflow component converts ADO Record sets it receives from the Business Logic Layer component, which is, in turn, converted into HTML for presentation. Workflow layer sits between the Presentation Layer and Business Logic Layer.

A business rules layer that contains the rules of how the user interacts with and manipulates the data via a data access layer. This layer might contain other layers as sub layers.

A data access layer that programmatically allows the business rules access to the stored data.