Retention Software Architecture

Retention software architecture comprises of secure and managed layers.

The Data Layer: The data layer is split into two separate layers. The first consists of the set of stored procedures implemented directly within the database. These stored procedures run on the server and provide basic data only. Not only are they pre-compiled and pre-optimized, but they can also be tested separately and, in the case of SQL Server 2000, run within the Query Analyzer to make sure that there are no unnecessary table scans.

 

 

The next layer consists of a set of classes which call and handle the stored procedures. One class per group of stored procedures handles all 'Select', 'Insert', 'Update' and 'Delete' operations on the database. Each class follows OO design rules is the result of a single abstraction - in other words handles a single table or a set of related tables. These classes handle all requests to or from the actual database and provide a shield to the application data. All requests are passed through this layer and all concurrency issues are handled here. This allows data integrity to be maintained and ensures that no other source can modify the data in any way.

Later if the database changes for any reason; it can be easily modified to handle them without affecting any other layers. This considerably simplifies maintenance.

Business Rule Layer: This layer is implemented in order to encapsulate the business rules. The classes which implement the business functionality are placed here. They neither access data (except through the data layer) nor do they affect the display or presentation of this data to the user. By isolating this Business Logic, we are able to concentrate on the guts of our system without the worry of design, workflow, or database access and related concurrency problems. If the business changes, only the business layer is affected, again considerably simplifying future maintenance and/or enhancements.

Workflow Layer This is one of the optional layers and deals with data flow to and from the system. It may or may not interact directly with the user interface, but always deals with external data sources.

Presentation Layer This layer handles everything to do with the presentation of the system. This layer includes the WebPages (or the user interface) and also all the classes which will help you present the data.

Ideally, the event method implementations within the form classes will only contain calls to the presentation layer classes. The web or windows forms used for visual representation interfaces seamlessly with the presentation layer classes, which handle all translations between the business layer/workflow layer and the forms themselves. This means that any changes on a visual front can be implemented easily.

Functional Block