Creating a Data Link 

A data link is a logical entity of a Web Dynpro application. The data link symbolizes data transfer between two entities of a Web Dynpro application; you can define several data links for an application. Data links can represent data flow definitions between the following:

·        A view and a component controller (data binding)

·        A view and a custom controller (data binding)

·        A component controller and a custom controller (mapping)

·        A component controller and an interface controller (mapping)

·        A custom controller and an interface controller (mapping)

·        A component controller and a model (model binding)

·        A custom controller and a 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

Before you create a data link, you must define a Project and a Web Dynpro Component. You must also have created all the entities that are to be involved in the data flow scenario to be defined.

Procedure

Carry out the following steps:

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

       2.      Choose Create Data Link from the tool selection area, which contains the Data Modeler actions.

       3.      To create a data link, 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, the 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. With the data link definition, you have implemented a data flow between the two Web Dynpro application entities.