Creating Data Links 

A data link is a logical entity of a Web Dynpro application which symbolizes data transfer between two controller units. You can define one or more data links for the application, this depends on your application design. Data links represent data flow definitions between the following controller types:

●      View and component controller (data binding)

●      View and custom controller (data binding)

●      Component controller and custom controller (mapping)

●      Component controller and interface controller (mapping)

●      Custom controller and interface controller (mapping)

●      Component controller and model (model binding)

●      Custom controller and model (model binding)

You define a data link graphically using the Data Modeler tool. There is a wizard for the data link that allows you to define the data flow between two entities using drag & drop.

Prerequisites

All the application units that are to be involved in the data flow scenario must be available.

Procedure

       1.      Open the Data Modeler by choosing the relevant context menu entry for the component name in the Web Dynpro Explorer. Choose Create Data Link.

       2.      Draw a line from the uppermost application entity in the Data Modeler to the lower, second entity. Once a plug symbol appears in the target entity to symbolize the link connect between the two entities, a wizard is started in which you can make the relevant entries.

Example

To define the mapping between a view and a custom controller, choose Create Data Link from the Data Modeler actions. Position the cursor on the green view box in the work area of the Data Modeler and draw a line to the blue custom controller box. Wait till the plug symbol appears. The mapping wizard is then opened.

The context trees displayed in the wizard represent the context definitions you may already have made using the Controller/Context Editor. However, the mapping wizard also allows you to create new nodes and attributes.

Result

After you have created the data link, it is displayed in the Web Dynpro Explorer with a blue arrow below the starting entity, labeled with the name of the target entity. In the Data Modeler, a data link is represented by a black arrow.