Defining Compositions in OData UI Services

Create copies of the following repository objects and place them in your ABAP package. For the repository object names, take the name of the template and replace /LRN/D437T with Z##. Make sure that the copies refer to your own repository objects and not to the template objects.

1. Create a copy of data definition /LRN/437T_C_TRAVELITEM (suggested name: Z##_C_TravelItem).

   1. In the Project Explorer view, locate the /LRN/437T_C_TRAVELITEM data definition in the /LRN/S4D437_TEMPLATE package and right-click it to open the context menu.

   2. From the context menu, select Duplicate....

   3. Enter the name of your package and the name for the copy. Choose Next.

   4. Assign the new object to a transport request and choose Finish.

2. Replace the selection target after the projection on keyword with the name of your own travel items view entity Z##_R_TravelItem and remove the root keyword.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      1234
      define view entity Z##_C_TravelItem
        provider contract transactional_query
        as projection on Z##_R_TravelItem
      {

3. Activate the data definition.

   1. Press Ctrl + F3 to activate the development object.

4. Create a copy of metadata extension /LRN/437T_C_TRAVELITEM (suggested name: Z##_C_TRAVELITEM).

   1. In the Project Explorer view, locate the /LRN/437T_C_TRAVELITEM metadata extension in the /LRN/S4D437_TEMPLATE package and right-click it to open the context menu.

   2. From the context menu, select Duplicate....

   3. Enter the name of your package and the name for the copy. Then choose Next.

   4. Assign the new object to a transport request and choose Finish.

5. Replace the CDS view after the annotate view keyword with your own projection view for travel items Z##_C_TravelItem.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      12
      annotate view Z##_C_TravelItem with
      {

6. Activate the data definition.

   1. Press Ctrl + F3 to activate the development object.

In the data definitions on projection level Z##_C_Travel and Z##_C_TravelItem, expose the associations from the underlying data model views. Make sure that the associations do not point at the views on data model level but that they are redirected to point at the respective views on projection level. Make sure that the associations keep their special character as composition and to parent association.

1. Edit the data definition of your projection view for travel items Z##_C_TravelItem. At the end of the projection list, add the name of the to parent association, which you defined in the underlying view entity.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      123
        LocChangedAt,
        _Travel
      }

2. Redirect the association to the projection view for flight travels.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      123
        LocChangedAt,
        _Travel : redirected to Z##_C_Travel
      }

3. Classify the redirected association as a to parent association.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      123
        LocChangedAt,
        _Travel : redirected to parent Z##_C_Travel
      }

4. Perform a syntax check.

   1. Press Ctrl + F2 and analyze the Problems view.

5. Remove or comment the provider contract addition, then activate the data definition.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      123
      define view entity Z##_C_Travelitem
        as projection on Z##_R_TravelItem
      {

   2. Press Ctrl + F3 to activate the development object.

6. Edit the data definition of your projection view for travels Z##_C_Travel. At the end of the projection list, add the name of the composition, which you defined in the underlying view entity.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      123
        LocChangedAt,
        _TravelItem
      }

7. Redirect the association to the projection view for flight travel items and classify it as composition.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      123
        LocChangedAt,
        _TravelItem : redirected to composition child Z##_C_TravelItem
      }

8. Activate the data definition.

   1. Press Ctrl + F3 to activate the development object.

Edit the behavior definition on projection level Z##_C_TRAVEL. Add a behavior projection for the child entity. Expose its etag definition and add the associations that establish the composition.

1. Edit the behavior definition on projection level Z##_C_TRAVEL. At the end of the source code, use a code template to add a new define behavior statement for the child entity Z##_C_TravelItem.

   1. After the last closing bracket, add a new code row, enter def, and press Ctrl + Space to invoke code completion.

   2. From the suggestion list, choose defineBehaviorFor - Define Behavior For.

   3. Replace entity with Z##_C_TravelItem.

   4. Remove or comment the alias addition.

2. Add the etag definition to the behavior projection.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      12345
      define behavior for Z##_C_TravelItem
      use etag
      {
      	
      }

3. For the child entity, add the standard operations update and delete to the projection.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      123456
      define behavior for Z##_C_TravelItem 
      use etag
      {
        use update;
        use delete;	
      }

4. Add the to parent association _Travel to the behavior projection of the child entity and the composition_TravelItem to the behavior projection of the root entity.

   Note

   Do not forget to draft-enable both associations and create-enable the composition.

   1. Add the following code to the behavior definition for the root entity:

      Code Snippet

      Copy codeSwitch to dark mode

      1
      use association _TravelItem { create; with draft; }

   1. Adjust the behavior definition for the child entity as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      12345678
      define behavior for Z##_C_TravelItem
      use etag
      {
        use update;
        use delete;
      
        use association _Travel { with draft; }		
      }

5. Activate the behavior projection.

   1. Press Ctrl + F3 to activate the development object.

Add the child entity of your business object to your service definition Z##_TRAVEL and extend the UI metadata of the service to display a list of child entities in a second facet on the object page for flight travels.

1. Open your service definition Z##_TRAVEL and add the projection view for flight travel items. Then activate the service definition.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      12345
      @EndUserText.label: 'Flight Travel Service Definition'
      define service Z##_TRAVEL {
        expose Z##_C_Travel;
        expose Z##_C_TravelItem;
      }

   1. Press Ctrl + F3 to activate the development object.

2. Open your service binding Z##_UI_TRAVEL_O2 and analyze the information under Entity Set and Association.

   Note

   There is no Refresh button available in service bindings but you can press F5 to reload the service binding.

3. Open the metadata extension for flight travels Z##_C_TRAVEL and locate the @UI.facet annotation. Inside the square brackets, add a comma (,) after the closing curly bracket and insert a copy of the existing facet definition.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      123456789101112
      @UI.facet: [ { id:            'Travel',
                     purpose:       #STANDARD,
                     type:          #IDENTIFICATION_REFERENCE,
                     label:         'Travel',
                     position:      10 }, 
      
                   { id:            'Travel',
                     purpose:       #STANDARD,
                     type:          #IDENTIFICATION_REFERENCE,
                     label:         'Travel',
                     position:      10 }
                 ]

4. Adjust the second facet definition according to the following table:

   Property	Value
   id	'TravelItem'
   purpose	#STANDARD
   type	#LINEITEM_REFERENCE
   label	'Travel Items'
   position	20

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      123456789101112
      @UI.facet: [ { id:            'Travel',
                     purpose:       #STANDARD,
                     type:          #IDENTIFICATION_REFERENCE,
                     label:         'Travel',
                     position:      10 }, 
      
                   { id:            'TravelItem',
                     purpose:       #STANDARD,
                     type:          #LINEITEM_REFERENCE,
                     label:         'Travel Items',
                     position:      20 }
                 ]

5. Inside the second facet definition, add the property targetElement with the name of the composition as value.

   1. Adjust the code as follows:

      Code Snippet

      Copy codeSwitch to dark mode

      12345678910111213
      @UI.facet: [ { id:            'Travel',
                     purpose:       #STANDARD,
                     type:          #IDENTIFICATION_REFERENCE,
                     label:         'Travel',
                     position:      10 }, 
      
                   { id:            'TravelItem',
                     purpose:       #STANDARD,
                     type:          #LINEITEM_REFERENCE,
                     targetElement: '_TravelItem',
                     label:         'Travel Items',
                     position:      20 }
                 ]

6. Activate the metadata extension and retest the preview for the OData UI service. Make sure that the object page for flight travels displays an (empty) list of flight travel items and that you can create new flight travel items.

   1. Press Ctrl + F3 to activate the development object.

   2. Open the service binding, place the cursor on the root entity and choose Preview....

   3. In the preview, display the details for one of the travels.

      Result

      The object page consists of two facets. The first facet shows the flight travel details and the second facet a list of the related flight travel items. This list is empty.

   4. Choose Edit to change to edit mode.

      Result

      On the second facet, you now see a Create button above the list of flight travel items.

   5. Choose Create and Apply to create a new travel item with initial values in all input fields.

      Result

      The list of travel items now contains one entry with initial values.

   6. Choose Save to save your changes.