Enhance an ABAP Core Data Services (CDS) View in ABAP On-Premise

To make the input fields more useful, you will now add input value help to the field AgencyID.

1. Specify the source of the value help. This works a bit like a join: You need to point to an entity, and field common to both the entity and your CDS view. In this case, you will point to AgencyID in the CDS entity /DMO/I_Agency. Add the following annotation to your field AgencyID.

   CDS

   Copy

   @Consumption.valueHelpDefinition: [{  entity: {name: '/DMO/I_Agency', element: 'AgencyID'}  }]
   
   

2. You also need to expose this second entity in the OData service. To do this, add the entity /DMO/I_Agency to your service definition, so the complete definition looks like this:

   CDS

   Copy

   @EndUserText.label: 'Service exposes Travel Data 005'
   define service Z_EXPOSE_TRAVEL_005 {
     expose Z_C_TRAVEL_DATA_005 as Travel;
     expose /DMO/I_Agency as Agency;
   }
   
   

3. Format, save, and activate both CDS view and service definition ( Shift+F1, Ctrl+S, Ctrl+3 ).

4. Refresh your Fiori Elements preview and choose value help for the input field AgencyID.

   

5. Now the value help appears. Enter the country key DE and choose Go. Only German agencies appear on the list.

   

6. Repeat this step for CustomerID:

   CDS

   Copy

   @Consumption.valueHelpDefinition: [{entity: {name: '/DMO/I_Customer', element: 'CustomerID' }}]
   

7. Also, expose this entity in the service definition:

   CDS

   Copy

   expose /DMO/I_Customer as Customer;
   
   

Next, you will make the Agency field more readable by adding the agency name to the ID, using a text association.
CDS associations are simply specifications of joins, always in the same place in the syntax. The main advantage of an association is reuse: Once you have specified an association once, you can conveniently string several associations together in a path. In this case, however, you will use a simple association.

For more information, see:
- ABAP Keyword Documentation: CDS - Associations

1. Add the following statement to your CDS view, Z_I_TRAVEL_R_XXX, just before the list of fields. The first statement creates an association from the source CDS entity Z_I_TRAVEL_R_XXX to the target CDS entity /DMO/I_Agency, joined on the field AgencyID. The source entity is represented by the alias $projection, because you cannot use the original name in a path statement. The target entity is represented by its alias name _Agency.

   CDS

   Copy

     association [1..1] to /DMO/I_Agency as _Agency on $projection.AgencyID = _Agency.AgencyID
   
   

   

2. Now add the following annotation to the field AgencyID:

   CDS

   Copy

     @ObjectModel.text.association: '_Agency'
   
   

3. Check that the association is included in the field list. (This should have been done automatically when you inserted the signature of /DMO/I_TRAVEL_U.)

   

4. Format, save, and activate ( Shift+F1, Ctrl+S, Ctrl+F3 ).

5. Make sure that the entity /DMO/I_Agency has been added to your service definition. (You should have done this in step 1.)

   

6. Refresh your Fiori Elements preview. The agency name should now be shown, with the ID number in parentheses.

   

7. Repeat for the fields CustomerID and Currency_Code:

   CDS

   Copy

   association [1..1] to /DMO/I_Customer as _Customer    on $projection.CustomerID =   _Customer.CustomerID
   association [0..*] to I_CurrencyText as _CurrencyText on $projection.CurrencyCode = _CurrencyText.Currency
   
   

   CDS

   Copy

   @ObjectModel.text.association: '_Customer'
   @ObjectModel.text.association: '_CurrencyText'
   
   

8. Also make sure these associations are added to the list of fields:

   CDS

   Copy

   //Associations
   _Customer
   _CurrencyText
   
   

   

ABAP has many built-in SQL functions for both numeric and string fields.

For more information on these functions, see : ABAP Keyword Documentation: SQL Functions.

You will use a simple one to easily merge two fields. The two fields are provided by the association _Customer.

1. Check that you have added the following association.

   CDS

   Copy

       association [1..1] to /DMO/I_Customer as _Customer on $projection.CustomerID = _Customer.CustomerID
   
   

2. Ensure there is a comma after CustomerID, then add the function concat_with_space using auto-complete ( Ctrl+Space ); then add the alias as Addressee and end with a comma.

   CDS

   Copy

     concat_with_space(_Customer.Title, _Customer.LastName, 1) as Addressee,
   
   

   

3. Also make sure this association is added to the list of fields:

   CDS

   Copy

   
   //Associations
   _Customer
   
   

4. Format, save, and activate these objects using Shift+F1, Ctrl+S, Ctrl+F3.

5. Check the result in the data preview, by clicking in the editor and choosing Open With > Data Preview from the context menu. The result should look like this.
   If not, make sure that you have selected the Addressee field in Settings.

   

   
   

   

6. Now you have the addressee, you may want to comment out the text association for CustomerID.

It would be nice to find out how much money each Agency has received in total. To do this, you first need to convert all the sums paid to one currency. To do this, you will again use a built-in function. For more information, see the ABAP Keyword Documentation: ABAP CDS - Conversion Functions for Units and Currencies

1. Convert the price (**TotalPrice**) of each line item to US Dollars. Again, you do this using a built-in conversion function. You simply have to define the variables you are using for amount, source currency, etc, and the built-in function does the rest.

   You need to cast the character value 'USD' to the correct type and length, abap.cuky( 5 ).

   You may get a warning: “Reference information missing…”. Ignore this.

   CDS

   Copy

   @Semantics.amount.currencyCode: 'CurrencyCode'
   currency_conversion(
   amount => TotalPrice,
   source_currency => CurrencyCode,
   round => 'X',
   target_currency => cast('USD' as abap.cuky( 5 )),
   exchange_rate_date => cast('20200429' as abap.dats),
   error_handling => 'SET_TO_NULL' )
   as PriceInUSD,  
   
   

2. Format, save, and activate ( Shift+F1, Ctrl+S, Ctrl+3 )

3. If you check the result in the data preview, it should look like this.

   

4. If you check it in Fiori Elements preview, it should look like this. You may want to filter for a specific currency, e.g. Singapore Dollars (SGD).

   

1. Add the following annotation to the element total_price, using Auto-complete (**Ctrl+Space**):

   ABAP

   Copy

   @DefaultAggregation: #SUM
   

   By using Auto-complete, you can see the various possibilities for aggregation, e.g. AVG, COUNT, SUM. In this case, we aggregate the SUM payable to each company.

2. Format, save, and activate ( Shift+F1, Ctrl+S, Ctrl+3 ).

1. Refresh your Fiori Elements preview. You may notice that a different grid control is used.
2. Right-click on Agency ID and choose Group:

   .
   

   

   This groups and aggregates the entries (Travels) by Agency ID. You can also see the sum of all travels for each agency, in US dollars.

   

3. Now, right-click on the Customer ID header and again choose Group.
   This displays a two-step grouping. You can browse and expand the companies and browse / expand the associated sales orders.

   

The grouping will be gone each time you refresh the application. To avoid this, add the following annotation to the metadata extension definition on view level (at the top):

@UI.presentationVariant: [{groupBy: [ 'AgencyID' , 'CustomerID' ]}]

The code for your CDS entity should look like this:

@AbapCatalog.viewEnhancementCategory: [#NONE]
@AccessControl.authorizationCheck: #NOT_REQUIRED
@EndUserText.label: 'Travel Model View Entity - Read Only'
@Metadata.ignorePropagatedAnnotations: true
@Metadata.allowExtensions: true
@Search.searchable: true
@ObjectModel.usageType:{
  serviceQuality: #X,
  sizeCategory: #S,
  dataClass: #MIXED
}

define view entity Z_I_TRAVEL_R_XXX
  as select from /DMO/I_Travel_U as Travel

  association [1..1] to /DMO/I_Agency   as _Agency       on $projection.AgencyID = _Agency.AgencyID
  association [1..1] to /DMO/I_Customer as _Customer     on $projection.CustomerID = _Customer.CustomerID
  association [0..*] to I_CurrencyText  as _CurrencyText on $projection.CurrencyCode = _CurrencyText.Currency


{

        ///DMO/I_Travel_U

  key TravelID,

      @Consumption.valueHelpDefinition: [{  entity: {name: '/DMO/I_Agency', element: 'AgencyID'}  }]
      @ObjectModel.text.association: '_Agency'
      AgencyID,

      @Consumption.valueHelpDefinition: [{entity: {name: '/DMO/I_Customer', element: 'CustomerID' }}]
      @ObjectModel.text.association: '_Customer'
      CustomerID,

      concat_with_space(_Customer.Title, _Customer.LastName, 1) as Addressee,
      BeginDate,
      EndDate,

      @Semantics.amount.currencyCode: 'CurrencyCode'
      BookingFee,

      @Semantics.amount.currencyCode: 'CurrencyCode'
      @DefaultAggregation: #SUM
      TotalPrice,


      @Semantics.amount.currencyCode: 'CurrencyCode'
      currency_conversion(
      amount => TotalPrice,
      source_currency => CurrencyCode,
      round => 'X',
      target_currency => cast('USD' as abap.cuky( 5 )),
      exchange_rate_date => cast('20200429' as abap.dats),
      error_handling => 'SET_TO_NULL' )                         as PriceInUSD,

      @ObjectModel.text.association: '_CurrencyText'
      CurrencyCode,

      @Search.defaultSearchElement: true
      @Search.fuzzinessThreshold: 0.90
      Memo,
      Status,
      LastChangedAt,

      /* Associations */
      _Agency,
      _Booking,
      _Currency,
      _CurrencyText,
      _Customer,
      _TravelStatus
}

At the moment, your application is a simple list. It would be nice to click on a row, i.e. a travel, and get more details in a separate page, known as an object page. Later you can add details from other CDS entities using associations.
For more information on object pages, see SAP Help Portal: Defining UI Annotations

1. First add the page itself. Go to your metadata extension and add the following annotation, just after the opening curly bracket:

   CDS

   Copy

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

   

2. You then specify which elements you want to include in the object page. Since the facet type is #IDENTIFICATION_REFERENCE, you use the identification annotation, so that the complete annotation plus element now looks like this:

   CDS

   Copy

   @UI: { lineItem:     [ {  position: 20, label: 'Agency', importance: #HIGH } ],
    identification:[ { position: 10, label: 'Travel' } ],
    selectionField: [{position: 20  }] }
   TravelID;
   
   

3. Add the following to the other elements, so that your metadata extension looks like this:

   CDS

   Copy

   @UI: { lineItem:     [ {  position: 20, label: 'Agency', importance: #HIGH } ],
        identification: [ { position: 20 } ],
        selectionField: [{position: 20  }]
       }
   AgencyID;
   
   
   @UI: { lineItem:        [ {  position: 30, label: 'Customer', importance: #HIGH  } ]
          ,identification: [ { position: 30 } ]
          ,selectionField: [ { position: 30 }]
         }
   CustomerID;
   
   
   @UI: {  lineItem: [ { position: 40 } ],
           identification: [ { position: 40 } ],
           selectionField: [ { position: 40 }]
         }
   BeginDate;
   
   
   @UI: {  lineItem: [ { position: 50 } ],
           identification: [ { position: 50 } ]
          ,selectionField: [ { position: 50 }]
         }
   EndDate;
   
   
   @UI: { lineItem: [ { position: 60 } ],
           identification: [ { position: 50 } ]
   
          }
   TotalPrice;
   
   

4. Finally, add a header to your object page, just after the layer annotation (before the annotate view... statement):

   CDS

   Copy

   @UI: {
     headerInfo: {
       typeName: 'Travel',
       typeNamePlural: 'Travels',
       title: {
         type: #STANDARD,
         label: 'Travel',
         value: 'TravelID'
       }
     }
   }
   
   

   

5. Test your object page in the Fiori Elements preview. It should look roughly like this:

   

You will now add more information to the object page by creating:
- A CDS entity for bookings
- Adding a second UI facet to the travel metadata extension

You will also create a parent-child hierarchy for these two entities. Your business object will then consist of a tree of nodes linked by a special associations known as a composition.
For more information on this relationship, see Defining the Data Model in CDS Views, particularly the first two sections, Travel Root View /DMO/I_Travel_U and Booking View /DMO/I_Booking_U.

1. In the Package Explorer, select Data Definition, then choose New Data Definition from the context menu.

   

2. Enter the following:

   • Name = Z_I_BOOKING_XXX
   • Description = Consumption view from /DMO/I_BOOKING_U
   • Referenced Object = /DMO/I_BOOKING_U

3. Choose the same transport request, then choose Next. Do not choose Finish.

4. Finally, choose Use template then choose Define view entity with To-Parent Association. Then choose Finish.

Your CDS entity appears in a new editor. We will fix the errors now.

1. Change the @AccessControl.authorizationCheck: to #NOT_REQUIRED.

1. Add the following to Z_I_BOOKING_XXX, using Auto-complete (Ctrl+Space).
   Then Save, but DO NOT yet activate your entity.

   CDS

   Copy

   association to parent Z_I_TRAVEL_R_XXX as _Travel
     on $projection.TravelID = _Travel.TravelID
   
   

2. Change Z_I_TRAVEL_R_XXX to a root view entity and add the composition association as follows. Again, Save, but DO NOT yet activate your entity.

   CDS

   Copy

   define root view entity Z_I_TRAVEL_R_XXX
     as select from /DMO/I_Travel_U as Travel
   
   composition [0..*] of Z_I_BOOKING_XXX as _Booking
   
   

3. Now, choose Activate All (Shift+Ctrl+F3).

   

4. Choose Deselect All, then choose your two entities Z_I_TRAVEL_R_XXX and Z_I_BOOKING_XXX, then choose Activate.

   

5. Change the @AccessControl.authorizationCheck: to #NOT_REQUIRED.

6. Add an alias to the define view statement, so that your code looks like this:

   CDS

   Copy

   @AccessControl.authorizationCheck: #CHECK
   @EndUserText.label: 'Read-only view from /DMO/I_BOOKING_U'
   define view entity Z_I_BOOKING_XXX as select from /DMO/I_Booking_U as Booking
   
   

7. Format, save, and activate the CDS entity (**Shift+F1, Ctrl+S, Ctrl+F3**) Z_I_BOOKING_XXX.

1. Add semantic annotations as follows:

   CDS

   Copy

   @Semantics.amount.currencyCode: 'Currency_Code'
   FlightPrice          as Flight_Price,
   
   @Semantics.currencyCode: true
   CurrencyCode         as Currency_Code,
   
   

2. Format, save, and activate the CDS entity (**Shift+F1, Ctrl+S, Ctrl+F3**).

1. First, allow metadata extensions to Z_I_BOOKING_XXX by adding the following annotation just after the @EndUserText.label: 'Consumption view from /DMO/I_BOOKING_U' annotation:

   CDS

   Copy

   @Metadata.allowExtensions: true
   
   

2. In the Package Explorer, select the CDS entity Z_I_BOOKING_XXX, then choose New Metadata Extension from the context menu.

3. Enter a name ZMDE_I_BOOKING_XXX and description Metadata forZ_I_BOOKING_XXX; select the transport request and choose Finish.,

4. In the editor, enter the following code:

   CDS

   Copy

   @Metadata.layer: #CORE
   
   @UI: {
   headerInfo: {
   typeName: 'Travel',
   typeNamePlural: 'Travels',
             title: {
               type: #STANDARD,
               label: 'Travel',
               value: 'TravelID'
                   }
             }
         }
   annotate view Z_I_BOOKING_XXX with
   
   {
     @UI: { lineItem:       [ { position: 10, importance: #HIGH } ],
            identification: [ { position: 10 } ] }
    TravelID;
   
     @UI: { lineItem:       [ { position: 10, importance: #HIGH } ],
            identification: [ { position: 10 } ] }
     BookingID;
   
     @UI: { lineItem:       [ { position: 20, importance: #HIGH } ],
            identification: [ { position: 20 } ] }
     BookingDate;
   
     @UI: { lineItem:       [ { position: 30, importance: #HIGH } ],
            identification: [ { position: 30 } ] }
     AirlineID;
   
     @UI: { lineItem:       [ { position: 40, importance: #HIGH } ],
            identification: [ { position: 40 } ] }
     ConnectionID;
   
   
     @UI: { lineItem:       [ { position: 50, importance: #HIGH } ],
            identification: [ { position: 50 } ] }
     FlightDate;
   
     @UI: { lineItem:       [ { position: 60, importance: #MEDIUM } ],
            identification: [ { position: 60 } ] }
     FlightPrice;
   
   }
   
   

5. Format, save, and activate the metadata extension (**Shift+F1, Ctrl+S, Ctrl+F3**).

1. Add the entity Z_I_BOOKING_XXX to the service definition Z_EXPOSE_travel_XXX with the alias Booking:

   CDS

   Copy

   @EndUserText.label: 'Expose travel Service XXX'
   define service Z_EXPOSE_travel_XXX {
     expose Z_C_travel_xxx as Travel;
     expose Z_I_BOOKING_XXX as Booking;
   
   

2. Format, save, and activate (**Shift+F1, Ctrl+S, Ctrl+F3**).

3. Check the service binding. It should now include a to_Booking association, like this. If not, try choosing Unpublish, then Publish again.

   

1. In metadata extension Z_TRAVEL_METADATA_XXX, before the square bracket, insert a comma after the Travel facet, then insert the Booking facet to the Travel metadata extension, so that your code looks like this:

   CDS

   Copy

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

   

2. Now, in the metadata extension ZMDE_I_BOOKING_XXX, specify which fields from Booking you want to include in the object page, again using an identification annotation as follows:

   CDS

   Copy

   @UI: { lineItem:       [ { position: 10, importance: #HIGH } ],
          identification: [ { position: 10 } ] }
   BookingID;
   
   @UI: { lineItem:       [ { position: 20, importance: #HIGH } ],
          identification: [ { position: 20 } ] }
   BookingDate;
   
   @UI: { lineItem:       [ { position: 30, importance: #HIGH } ],
          identification: [ { position: 30 } ] }
   AirlineID;
   
   @UI: { lineItem:       [ { position: 40, importance: #HIGH } ],
          identification: [ { position: 40 } ] }
   ConnectionID;
   
   
   @UI: { lineItem:       [ { position: 50, importance: #HIGH } ],
          identification: [ { position: 50 } ] }
   FlightDate;
   
   @UI: { lineItem:       [ { position: 60, importance: #MEDIUM } ],
          identification: [ { position: 60 } ] }
   Flight_Price;
   
   

3. Test your new facet in the Fiori Elements preview. It should roughly look like this:
   

You can also display information from another entity using an association.

1. In the CDS entity Z_I_BOOKING_XXX, add an association from Booking to Connection.

   CDS

   Copy

       association [1..1] to /DMO/I_Connection as _Connection on $projection.ConnectionId = _Connection.ConnectionID
   
   

2. You may get a warning. If so, choose Problem Description; you will see that this warning can be hidden, by adding the following pseudo-comment:

   CDS

   Copy

     /*+[hideWarning] { "IDS" : [ "CARDINALITY_CHECK" ] }*/
   
   

3. Now add the following two elements to the CDS entity Z_I_BOOKING_XXX:

   CDS

   Copy

   @Semantics.quantity.unitOfMeasure: 'DistanceUnit'
   _Connection.Distance as Distance,
   
   _Connection.DistanceUnit as DistanceUnit,
   
   

4. Add the following to your service definition, Z_EXPOSE_TRAVEL_R_XXX.

   CDS

   Copy

   expose /DMO/I_Connection as Connection;
   
   

5. Optional: Test your Fiori Elements preview again. It should look like this:

   

   If not, make sure that you have selected the field Flight Distance from Settings.

1. Add the following code, immediately after the element DistanceUnit:
   CDS

   Copy

   case
       when _Connection.Distance >= 2000 then 'long-haul flight'
       when _Connection.Distance >= 1000 and
        _Connection.Distance <  2000 then 'medium-haul flight'
       when _Connection.Distance <  1000 then 'short-haul flight'
                         else 'error'
   end                      as Flight_type,
   
   

2. Also, make sure that the distance is in kilometers, by adding this code after the select list:
   CDS

   Copy

   where
   _Connection.DistanceUnit = 'KM'
   
   

   

3. Format, save, and activate the CDS entity.

4. Test your Fiori Elements preview again. It should look like this:

   

• Blog post: From Open SQL Joins to CDS Associations

• SAP Help Portal: Defining UI Annotations

• SAP Help Portal: Defining CDS Annotations for Metadata-Driven UIs

• Troubleshooting: Blog post: Find Errors in Metadata Extensions, by Andre Fischer

• Troubleshooting: Blog post: Use the SAP Gateway Error Log in ADT, by Andre Fischer