Designing Client/Server Applications › Types of Logic

Types of Logic

For purposes of distribution, it is possible to divide application software into three distinct types of logic:

• Presentation, which is associated with the user interface
• Business rule, which is associated with accomplishing a basic business process
• Data manipulation, which is associated with reading and writing persistent data

Presentation logic is associated with a procedure step definition. Business rule logic and data manipulation logic are generally found in elementary processes or process action blocks. In some applications, little or no business logic exists except for that directly governing data.

In simple client/server applications, these three types of logic can be divided into two components executing on different machines, one for presentation and one for data manipulation. Business rule logic is generally embedded in whichever component it appears to make sense, or it may be segmented into reusable action blocks. One reason for putting business rule logic in a reusable component is that you can easily generate and install the component for a different platform.

You do not have to decide what processing logic is required to support network communications. CA Gen for client/server products includes a communications runtime for you. For more information about the communications runtime components, see the Distributed Processing - Overview Guide.

The important task to remember is to design client/server applications to be modular and flexible. Maintain a clear distinction between presentation logic, business rule logic, and data manipulation logic so that you can change between client/server styles as needed. Maintain data manipulation logic as separate action diagrams or common action blocks to be used by server procedures. This approach also allows many client procedures to use the server procedures.