Extending Existing Model

After you have added the artifacts for your service in the Service Builder, there might be instances when you would want to add more artifacts without overwriting the model. In such cases, you can use the Extend Current Model option and select the artifacts from the model that was redefined. In such cases, the Technical Service Name field in the Select Service region is read-only and displays the specific service from which you can add more artifacts.

1. Log onto the SAP Gateway system.

2. Open transaction SEGW.

   The SAP Gateway Service Builder opens.

3. Open an existing project to be redefined.

4. Choose Edit to switch to editing mode.

5. Right-click on the Data Model folder and in the resulting submenu, select  Redefine Service  OData Service (SAP GW) 

   The Wizard Step 1 of 2: Redefine Service wizard opens.

6. Select the Extend current model radio button.

   The Technical Service Name field in the Select Service region displays the source model's technical service name and the version. This field is read-only.

7. If the metadata of the selected service resides in another system, select Metadata to be fetched from an external system. in the Target System for Metadata.

8. On the selection of the Metadata to be fetched from an external system the RFC Destination field becomes editable to select the RFC destination of the external system using the input help.

9. Choose Next to continue.

   Note

   If the RFC destination is incorrect, an error message is displayed.

10. On successful validation of the RFC destination, the Wizard Step 2 of 2: Redefine Service opens.

    Note

    The artifacts that were already selected will be read-only.

11. Select the required artifacts.

    There is a selection logic in the backend, which automatically includes all the entity types that are end types/return type of chosen association/function import. The reverse is not selected. For example, consider the following model:

    Example

    COMPLEX TYPES

    • complex_type_1

    • complex_type_2

    ENTITY TYPES

    • entity_type_1

    • entity_type_2

    • entity_type_3

    ASSOCIATIONS

    • association_1 (between Entity_type_1 & Entity_type_2)

    • association_2 (between Entity_type_1 & Entity_type_3)

    FUNCTION IMPORTS

    • function_import_1

    Case1: User selects Entity_Type_1, Entity_Type_2 and Association_1. All these entities are selected and used in the new model. If Entity_Type_1 & Entity_Type_2 uses Complex_Type_1 & Complex_Type_2, they are automatically selected.

    Case2: User selects Entity_Type_1, Association_2. Since Entity_Type_3 is part of the Association_2, Entity_Type_3 is selected automatically along with Entity_Type_1 and Association_2.

12. Add more artifacts as required and choose Finish.

    The added artifacts are displayed in the tree view under the appropriate folder.

13. Choose Finish after you have made the relevant selections.

14. The Service Builder performs the consistency check of the imported model and a message is displayed. The selected artifacts are then transferred to the respective folders in the tree view of the Service Builder. Also, an entry with the name and the version of the service selected for redefinition is created under the Model Reference folder in the Service Builder.

15. Double-click the referenced model and the mass maintenance view displays Model Reference Type as Extend to indicate that this model can be extended.

    Note

    If the model has been referenced as an Include, the model reference type displayed is Include instead of Extend.

16. You can perform the following redefinitions for the model imported:

    • Delete the artifacts.

    • Change the Node Names and Labels.

      1. Switch to edit mode.

      2. Choose the Redefine Attribute button.

         The Node Name and the Label fields can be edited.

      3. Choose the Undo Redefinition button to revert the redefined value to the original value.

      4. Choose the Undo Identical Redefinition button to view the fields which have been reverted to their original values in the course of editing.

    Caution

    During redefinition of a service, changes to the external name and labels are allowed, but deleting a label is not supported. In case if you delete a label, the following will be the impact.

    • Metadata will not reflect the deletion and will still show the label.

    • There will be issues in the assignment of text keys to labels in the generated MPC, which will lead to incorrect label settings for other artifacts.

17. After you have completed the redefinition process, you can generate runtime objects.

    Note

    Generation of MPC and DPC:

    Case1: Overwrite Base/Extended Service - If you have redefined an existing service, an additional section Service Extension will appear in this wizard. Select Overwrite Base/Extended Service, to overwrite the contents of the referenced service class. This option allows you to access the redefined (new) service using the redefining (base) service URL. You can no longer access the redefining service using the same URL.

    Case2: Create a new service — A new service and a new model will be created and registered during the generation process.

    A new set of DPC classes will be generated.

    See Generating the Service for more information.

18. After the service has been generated, the MPC and DPC classes are stored in the Runtime Artifacts folder.