The OpenEdge Reference Architecture is a recommended approach to designing business applications according to current best practices. The reference architecture views an application as a set of layers that provide services to each other, as shown in the following figure. This model allows your business and support logic to be modularized for flexibility and reusability. You can use the reference architecture as a whole, or adopt it a piece at a time to fit your needs. The reference architecture separates business tasks into a set of layers.
Figure 3. OpenEdge Reference Architecture
The procedures in the Data Access layer manage handling data from your data stores. These procedures retrieve information from wherever it resides in the physical data stores and arrange the data into logical datasets that meet the business needs for the procedures in the Business Servicing layer. Other procedures in the Data Access layer extract the data changes from the logical datasets and commit the changes to the proper places in the physical data stores.
The procedures in the Business Servicing layer act on requests received from users through the Presentation layer or from enterprise services through the Integration layer. These procedures handle the business tasks required to fulfill an order, for example. The procedures in the Business Servicing also push data changes in the data sets back to the Data Access layer.
The procedures in the Presentation and Integration layers pass requests from external sources (users or enterprise services) to the Business Servicing layer. Procedures in these layers might prevalidate that user requests are complete and in the proper format. The main work of these layers is to transform incoming data into the form needed by the business logic of the Business Servicing layer and to properly present the results for the consumers.
