Key Mapping 
You can use this function to create mappings between object instances by connecting their object IDs.
In business processes with several systems, each object instance requires one or more object IDs to ensure it can be identified and mapped to other object instances. During data replication, the object instance is replicated from a central system to one or more target systems. In the process, each system can use its own logic to create object IDs.
To create, change, or delete key mapping information, you can complete the following actions:
Use the Create and Edit Key Mapping Web Dynpro application
For more information, see Creation, Editing, and Deletion of Key Mapping Information.
Call the key mapping Application Programming Interface (API) within your programs.
To access key mapping information directly, you can complete the following actions:
Use the Search Key Mapping Web Dynpro application.
For more information, see Searching of Key Mapping Information.
Call the key mapping Application Programming Interface (API) within your programs.
You can access key mapping information from the central registry of a client system. This is only possible if, in Customizing, you have defined a business system as a central registry for each business object that uses key mapping.
When you access key mapping remotely, you have the following options:
Extending key mapping for an existing object
With this option, you must define an object ID type and you may have to define an object node type for the object ID type.
Using key mapping for your own business objects
With this option, you must define an object ID type and an object node type for the object ID type.
Note
You can apply the relevant settings in Customizing for Master Data under .
For more information about data replication, see Data Replication.