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Enhance an ABAP Core Data Services (CDS) View in SAP Business Technology Platform (BTP) ABAP Environment

Add features like value help, aggregations, and calculated fields to an existing CDS entity
You will learn
  • How to add value help using a filter
  • How to add textual information using associations
  • How to concatenate two elements, using a built-in function for CDS
  • How to convert currencies using a built-in function for CDS
  • How to create an object page
  • How to create a parent-child hierarchy in your business object
  • How to add a CASE statement
julieplummer20Julie PlummerJanuary 25, 2022
Created by
julieplummer20
July 9, 2020
Contributors
julieplummer20

You can then use some of these features in productive development to make your applications more powerful and more user-friendly. By the end of this tutorial, your application should include a list page and an object page, which should look like this:

fep-final-enhance step13c-fep-CASE

You can see the code at the end of this tutorial. Throughout the tutorial, objects name include a suffix, such as XXX. Always replace this with your group number or initials.

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

    step10a-activate-all-toolbar
  4. Choose Deselect All, then choose your two entities Z_I_TRAVEL_R_XXX and Z_I_BOOKING_XXX, then choose Activate.

    step10-activate-all
  5. Change the @AccessControl.authorizationCheck: to #NOT_REQUIRED.

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

    @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.

[ACCORDION-END]

More Information

  • Step 1

    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 value help entity and your CDS entity. 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 XXX'
      define service Z_EXPOSE_TRAVEL_R_XXX {
        expose Z_I_TRAVEL_R_XXX as Travel;
        expose /DMO/I_Agency as Agency;
      }
      
      
    3. Format, save, and activate both CDS entity and service definition ( Shift+F1, Ctrl+S, Ctrl+3 ).

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

      step13a-choose-value-help
    5. Now the value help appears. Enter the country key DE and choose Go. Only German agencies appear on the list.

      step13b-german-agencies
    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;
      
      
  • Step 2

    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 entity, 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
      
      
      step14a-add-association
    2. Now add the following annotation to the field AgencyID:

      CDS
      Copy
        @ObjectModel.text.association: '_Agency'
      
      
    3. Check that the association has been added to the field list. (This should have been done automatically when you inserted the signature of /DMO/I_TRAVEL_U.)

      step14b-association-added
    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.)

      step2a-sd-added
    6. Refresh your Fiori Elements preview. The agency name should now be shown, with the ID number in parentheses.

      step14c-fep-agency-by-name
    7. Repeat for the field CustomerID:

      CDS
      Copy
      association [1..1] to /DMO/I_Customer as _Customer    on $projection.CustomerID =   _Customer.CustomerID
      
      
      CDS
      Copy
      @ObjectModel.text.association: '_Customer'
      
      
    8. Also make sure this association are added to the list of fields:

      CDS
      Copy
      //Associations
      _Customer
      
      
      step2b-associations-added
  • Step 3

    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. Add an association.

      CDS
      Copy
          association [1..1] to /DMO/I_Customer as _Customer on $projection.CustomerID = _Customer.CustomerID
      
    2. After CustomerID, add a comma, then add the function concat_with_space using auto-complete ( Ctrl+Space ); then add the alias as Addressee.

      CDS
      Copy
        concat_with_space(_Customer.Title, _Customer.LastName, 1) as Addressee,
      
      
      step15a-concat
    3. Also make sure this association is added to the list of fields:

      CDS //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.

      step3-settings-addressee

      step15b-concat-result
    6. Now you have the addressee, you may want to comment out the text association for CustomerID.

  • Step 4

    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 for now.

      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.

      step16a-currency-conversion
    4. Now you will remove the warning. If you select the warning, then choose Problem Description from the context menu, you will see that you need to add an annotation, •Semantics.amount.currencyCode. However, this will simply add the original currency code (e.g. NOK) to the PriceInUSD column. Also, you can only add an element name to the annotation, not a literal such as 'NOK'. So you need to:

      • Create a column, TargetCurrency
      • Give it the value of the literal
      • Cast the string literal to a currency type, abap.cuky
      • Add the semantic annotation to PriceInUSD

      Your code should now look like this:

      CDS
      Copy
      //Conversion to USD
      @Semantics.currencyCode: true
        cast( 'USD' as abap.cuky ) as TargetCurrency,
      
      
    5. Optional: Test in the Fiori Elements preview. Your app should look like this:
      step16b-convert-to-dollars
  • Step 5

    The code for your CDS entity should look like this:

    CDS
    Copy
    @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
    
      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
    
    {
    
          ///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,
          BookingFee,
    
          @Semantics.amount.currencyCode: 'CurrencyCode'
          TotalPrice,
    
          //Currency Conversion
          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 */
          //DMO/I_Travel_U
          _Agency,
          _Booking,
          _Currency,
          _Customer,
          _CurrencyText,
          _Customer,
          _TravelStatus
    
    }
    
    
  • Step 6

    In the currency conversion function, how can you change the setting of error handling so that, if there is an error, an exception is thrown. Use the ABAP Keyword Documentation for reference.

  • Step 7

    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. Add the following annotation to your metadata extension, just after the opening curly bracket:

      CDS
      Copy
      @UI.facet: [ { id:              'Travel',
                      purpose:         #STANDARD,
                      type:            #IDENTIFICATION_REFERENCE,
                      label:           'Travel',
                      position:        10 } ]
      
      
      step6a-add-ui-facet
    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'
          }
        }
      }
      
      
      step6c-header
    5. Test your object page in the Fiori Elements preview. It should look roughly like this:

      step6b-fep-preview-object-page
  • Step 8

    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.

      step7a-new-cds
    2. Enter the following:

      • Name = Z_I_BOOKING_R_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. 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.
  • Step 9
  • Step 10
    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**).

  • Step 11
    1. First, allow metadata extensions to your CDS entity 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_R_XXX, then choose New Metadata Extension from the context menu.

    3. Enter a name ZMDE_BOOKING_R_XXX and description Metadata forZ_I_BOOKING_R_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_R_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 } ] }
        Flight_Price;
      
      }
      
      
    5. Format, save, and activate the metadata extension (**Shift+F1, Ctrl+S, Ctrl+F3**).

  • Step 12
    1. Also, add the entity Z_I_BOOKING_R_XXX to the service definition Z_EXPOSE_TRAVEL_R_XXX:
    CDS
    Copy
    @EndUserText.label: 'Expose travel Service XXX'
    define service Z_EXPOSE_TRAVEL_R_XXX {
      expose Z_I_TRAVEL_R_XXX as Travel;
      expose Z_I_BOOKING_R_XXX as Booking;
    }
    
    
    1. Format, save, and activate (**Shift+F1, Ctrl+S, Ctrl+F3**).

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

      step10a-sb-w-booking-association
  • Step 13
    1. In metadata extension Z_MDE_TRAVEL_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'} ]
      
      
      step9a-add-facet-booking
    2. Now, in the metadata extension ZMDE_BOOKING_R_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 look like this:
      step9b-fep-booking-facet
  • Step 14

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

    1. In the CDS entity Z_I_BOOKING_R_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 will get a warning. If you 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_R_XXX:

      CDS
      Copy
      @Semantics.quantity.unitOfMeasure: 'DistanceUnit'
      _Connection.Distance as Distance,
      
      @Semantics.unitOfMeasure: true
      _Connection.DistanceUnit as DistanceUnit,
      
      
    4. Optional: Test your Fiori Elements preview again. It should look like this:

      step12a-fep-plus-connection
  • Step 15
    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'
      
      
      step13b-add-where-clause
    3. Format, save, and activate the CDS entity.

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

      step13c-fep-CASE
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