Working with Data Mappings 
You can use data mappings to define how the source context data is transformed to the target context data.
The SAP NetWeaver Developer Studio provides a mapping editor where you define these transformations by dragging and dropping from the source to the target data. The source and target contexts are represented in tree data structures on the left and right side of this editor. The SAP NetWeaver Developer Studio provides also an expression editor, which can be used for creating expressions over the context data that is used in transformations between data nodes. For more information, see Defining Data Mappings.
Each node in the context has a data type and cardinality. The data types that you can use are organized in clusters. When you create data mappings, not all data types are supported. For more information about type clusters and compatibility, see Data Type Compatibility.
Note
You can use data mappings in different layers of your composite application. For example, you can define data mappings in business processes of the Process layer, or over composed services in the Business Logic layer.
For more information about how to define data transformations, see Data Mapping Rules.