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Create an ABAP Core Data Services (CDS) View in SAP BTP, ABAP Environment

Create a CDS View, display it in Fiori Elements preview, and enhance its appearances using built-in annotations in the Business Technology Platform, ABAP Environment
You will learn
  • How to create a read-only CDS-based travel model
  • How to display your CDS view in a Fiori Elements preview
  • How to add selection fields to Fiori Elements preview
  • How to extract the metadata of your CDS view
  • How to add semantic annotations
  • How to add a search function
  • How to add selection fields to the Fiori Elements preview
julieplummer20Julie PlummerJanuary 25, 2022
Created by
julieplummer20
July 9, 2020
Contributors
julieplummer20

Prerequisites

In summary, based on existing persistent data sources, you will create and implement a query for an OData service to get a running app with useful read-only features. 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 look like this.

final-app-create

Throughout this tutorial, object names may include a suffix or group number, such as XXX. Always replace this with your own group number or initials.

For more information on creating a read-only app, see the SAP Help Portal: Developing Read-Only List Reporting Apps

  • Step 1
    1. Create a new package for this tutorial, by choosing New > ABAP Package.
      step1a-new-package
      1. Enter the following then follow the wizard, choosing a new transport request:
      • Name: Z_ENHANCE_CDS_XXX
      • Description Enhance CDS Tutorial 2020
        step1a-create-package
        step1b-new-tr
  • Step 2
    1. In your package, create a CDS view entity. Select the package, then choose New > Other from the context menu, then choose Data Definition.

      step2a-new-cds
      1. Add the following:
        • Name: Z_I_TRAVEL_R_XXX
        • Description: Travel Model View Entity - Read Only
        • Referenced object: /DMO/I_TRAVEL_U
        Your CDS view is a read-only view. It is based on the business object (BO) view, /DMO/I_TRAVEL_U.
    2. Choose or create a transport request, then choose Next. Do not choose Finish.

    3. Choose Use template then choose Define View Entity.

      step2b-choose-view-entity
    4. Finally, choose Finish.

    Your CDS entity appears in a new editor, with the elements (fields and associations) from the referenced data object, ``, already inserted. Ignore the error for now.

    step2b-cds-editor
  • Step 3
    1. You will see 2 errors - at BookingFee and TotalPrice. Add the following annotations:

      CDS
      Copy
      @Semantics.amount.currencyCode: 'CurrencyCode'
      BookingFee,
      
      @Semantics.amount.currencyCode: 'CurrencyCode'
      TotalPrice,
      
      
    2. Format, save, and activate your code by choosing Shift+F1, Ctrl+S, Ctrl+F3. It should look like this:

    CDS
    Copy
    @AbapCatalog.viewEnhancementCategory: [#NONE]
    @AccessControl.authorizationCheck: #CHECK
    @EndUserText.label: 'Travel Model View Entity - Read Only'
    @Metadata.ignorePropagatedAnnotations: 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
    
    {
      key TravelID,
          AgencyID,
          CustomerID,
          BeginDate,
          EndDate,
    
          @Semantics.amount.currencyCode: 'CurrencyCode'
          BookingFee,
    
          @Semantics.amount.currencyCode: 'CurrencyCode'
          TotalPrice,
    
          CurrencyCode,
          Memo,
          Status,
          LastChangedAt,
    
          /* Associations */
          _Agency,
          _Booking,
          _Currency,
          _Customer,
          _TravelStatus
    }
    
    

    If you define currency amounts and currency codes semantically, then the system will apply specific rules to handle these fields appropriately.
    For example, in this tutorial, if you define TotalPrice as a currency amount, then the system will add the appropriate currency to the TotalPrice column automatically. There is no need to display CurrencyCode as a separate column.

  • Step 4
    1. Click anywhere in the editor and choose Open With > Data Preview from the context menu.

      step4a-open-display-preview
    2. The Data Preview is displayed in a new tab. You can investigate the data, by filtering, specifying the number of rows, and so on. The values in LastChangedAt are not user-friendly, but you solve that by providing a Fiori elements preview in the next step.

      step4b-data-preview
  • Step 5

    You will now expose the CDS view as a business service. This will allow you to preview your changes in Fiori elements preview.

    A business service consists of a service definition and a service binding.

    You use a service definition to define which data is to be exposed (with the required granularity) as a Business Service.

    You then use the service binding to bind a service definition to a client-server communication protocol such as OData. This allows you to provide several bindings for the same definition, e.g. to expose the service to a UI, and to an A2X provider.

    For more information, see:

    1. First, create the service definition, by selecting your CDS view and choosing New > Service Definition from the context menu.

      step4a-new-sd
    2. Choose a name and description:

      • Z_EXPOSE_TRAVEL_R_XXX
      • Service exposes Travel data
      step4b-sd-travel-data
    3. Choose the transport request; choose Next.

    4. Use the selected template; choose Finish. The name of your custom entity is inserted automatically.

      step4d-sd-editor
    5. To make the service definition more readable, add an alias to the expose statement:

      CDS
      Copy
      expose Z_I_TRAVEL_R_XXX as Travel;
      
      
    6. Format, save, and activate ( Shift+F1, Ctrl+S, Ctrl+F3 ) the service definition.

  • Step 6
    1. Select your service definition, then choose Service Binding from the context menu, then choose Next.

      step5a-new-sb
    2. Choose:

      • Name = Z_BIND_TRAVEL_R_XXX
      • Description = Service binding for Travel data
      • Binding Type = ODATA V2 (UI…)
      • Service Definition = Z_EXPOSE_TRAVEL_R_XXX
      step5b-create-service-binding
    3. Choose the transport request; choose Finish.

    The service binding automatically references the service definition and thus the exposed custom entity.

  • Step 7
    1. In the editor that appears, choose Activate.

      step13-activate-service-endpoint
    2. You can now see the Service URL and Entity Set.

      step13b-entity-set
    3. To open the Service Document (XML) in your browser, choose Service URL.

      step13c-open-service-url
      step13e-service-xml-in-browser
    4. In the browser, you can also see the Metadata Document of the Business Service by adding $metadata to the URL: /sap/opu/odata/sap/Z_BIND_TRAVEL_R_XXX/$metadata.

      step13f-service-metadata-in-browser
  • Step 8
    1. Select the entity set and choose Preview.

      step7a-display-fep
    2. Log in using your ABAP Environment user and password; the Fiori Elements preview appears.

    3. By default, no columns are selected. To see the data, choose Settings, then choose Select All.

      step7b-settings
      step7c-select-all
    4. Display the data by choosing Go.

      step7d-fep-w-data
  • Step 9
    1. It would be nice if at least some fields were displayed immediately for the user. To do this, simply add the following annotation to the relevant fields in Z_I_TRAVEL_R_XXX. The start of the CDS view will then look like this.

      BookingFee is not automatically displayed. The numbers for each field are relative to the other fields and are responsive - they do not refer to a specific pixel position or similar. For larger entities, you can specify HIGH,*MEDIUM*, or LOW, so that less important fields are automatically hidden on a smaller screen, such as a mobile phone.

      CDS
      Copy
      @UI           : {
      lineItem      : [{position: 10, importance: #HIGH}]
      }
      key TravelID;
      
      @UI           : {
            lineItem      : [{position: 15, importance: #HIGH}]
            }
      AgencyID,
      
      @UI           : {
            lineItem      : [{position: 20, importance: #HIGH}]
            }
      CustomerID,
      
      @UI           : {
            lineItem      : [{position: 30, importance: #HIGH}]
            }
      BeginDate,
      
      @UI           : {
            lineItem      : [{position: 40, importance: #HIGH}]
            }
      EndDate,
      
      BookingFee,
      
      @UI           : {
            lineItem      : [{position: 50, importance: #HIGH}]
            }
      TotalPrice,
      
      
    2. If you now refresh your Fiori Elements preview, you will notice that you do not have to choose the fields; you simply have to choose Go.
  • Step 10

    At present, you only have minimal annotations. As you add more, your CDS view will start to get cluttered. So you should extract your UI annotations to a separate object, a metadata extensions object, as follows:

    1. First add the annotation @Metadata.allowExtensions: true to your CDS view.

    2. Then, click anywhere in the editor, then choose Source Code > Extract Metadata Extension from the context menu.

      step9a-extract-metadata
    3. Enter a name and description for your metadata extension object, clearly similar to your CDS view name, and choose Next:

      • Z_MDE_TRAVEL_XXX
      • Metadata for Z_I_TRAVEL_R_XXX
    4. Accept the transport request, choose Next, select all elements, then choose Finish.

      step9b-mde-select-elements
    5. You will get an error, because you have not yet assigned the metadata extension to a layer. Since you are in sandbox mode, enter the value #CORE using auto-complete ( Ctrl+Space ).

      step9c-assign-layer

      Layers allow customers or partners, for example, to enhance the metadata without modifying the CDS entity. You can also add industry- or country-specific enhancements.

      The metadata extensions are evaluated in a specific order. For more information, see Annotation Propagation.

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

  • Step 11

    If you define currency amounts and currency codes semantically, then the system will apply specific rules to handle these fields appropriately.
    For example, in this tutorial, if you define TotalPrice as a currency amount, and define CurrencyCode as a currency code field, then the system will add the appropriate currency to the TotalPrice column automatically. There is no need to display CurrencyCode as a separate column.

    1. To do this, add the following two annotations to your CDS view:
      CDS
      Copy

      @Semantics.amount.currencyCode: 'CurrencyCode' TotalPrice, @Semantics.currencyCode CurrencyCode,
    2. Format, save, and activate ( Shift+F1, Ctrl+S, Ctrl+3 ).
    3. If you refresh the Fiori Elements preview, the Total Price column now looks like this.

      step10a-currency-code
  • Step 12

    You will now add a fuzzy search capability.

    1. First, add the search annotation to your CDS view:

      CDS
      Copy
      @Search.searchable: true
      
    2. Then add the following two annotations to the field you want to search, in this case Memo:

      CDS
      Copy
      @Search.defaultSearchElement: true
      @Search.fuzzinessThreshold: 0.90
      
      
    3. For convenience, add the following annotation to the metadata extension object, so that the Memo field appears by default in the preview, then format, save, and activate ( Shift+F1, Ctrl+S, Ctrl+3 ):

      CDS
      Copy
      @UI           : {
            lineItem      : [{position: 60, importance: #HIGH}]
            }
      Memo;
      
      
    4. Refresh the Fiori elements preview in your browser.

    5. There is a new Search input field.

      step11a-search-field
    6. Enter the search text Miami. The app only displays trips to Miami (to date, eleven trips).

      step11b-miami-90
    7. Optional: You can test the fuzziness threshold by changing the value to 0.70. After you save and activate, the app will now show trips to Miami and trips involving Matthias. (You may need to empty the cache.)

      step11b-miami-70
  • Step 13

    As well as search fields, you can filter the list using an input field. In the next tutorial, you will provide input value help for these fields.

    1. Add the selectionField annotation to the field TravelID in your metadata extension file, so that the whole UI annotation looks like this:

      CDS
      Copy
      @UI           : {
            lineItem      : [{position: 10, importance: #HIGH}],
            selectionField: [{position: 10 }]
            }
      TravelID;
      
    2. Format, save, and activate ( Shift+F1, Ctrl+S, Ctrl+3 ). The Fiori elements preview should now look like this:

      step12a-selection-field
    3. Add other fields as input fields by adding the following to the metadata extensions file, so that the file looks like this:

      CDS
      Copy
      @UI           : {
            lineItem      : [{position: 15, importance: #HIGH}],
            selectionField: [{position: 15 }]
            }
      AgencyID;
      
      @UI           : {
            lineItem      : [{position: 20, importance: #HIGH}],
            selectionField: [{position: 20 }]
            }
      CustomerID;
      
      @UI           : {
            lineItem      : [{position: 10, importance: #HIGH}],
            selectionField: [{position: 10 }]
            }
      TravelID;
      
      @UI           : {
            lineItem      : [{position: 30, importance: #HIGH}],
            selectionField: [{position: 30 }]
            }
      BeginDate;
      
      @UI           : {
            lineItem      : [{position: 40, importance: #HIGH}],
            selectionField: [{position: 40 }]
            }
      EndDate;
      
      @UI           : {
            lineItem      : [{position: 50, importance: #HIGH}]
            }
      TotalPrice;
      
      @UI           : {
            lineItem      : [{position: 50, importance: #HIGH}]
            }
      Memo;
      
      @UI           : {
          lineItem      : [{position: 60, importance: #HIGH}],
          selectionField: [{position: 60 }]
          }
      Status;
      

      Your app should now look like this:

      step12b-all-selection-fields-preview
  • Step 14

    Your CDS entity code should look like this:

    CDS
    Copy
    @AbapCatalog.viewEnhancementCategory: [#NONE]
    @AccessControl.authorizationCheck: #CHECK
    @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 Z_I_TRAVEL_R_XXX as Travel
      as select from /DMO/I_Travel_U  as Travel
    
    {
    
          ///DMO/I_Travel_U
    
    
      key TravelID,
          AgencyID,
          CustomerID,
          BeginDate,
          EndDate,
    
          @Semantics.amount.currencyCode: 'CurrencyCode'
          BookingFee,
    
          @Semantics.amount.currencyCode: 'CurrencyCode'
          TotalPrice,
    
          CurrencyCode,
    
          @Search.defaultSearchElement: true
          @Search.fuzzinessThreshold: 0.90
          Memo,
    
          Status,
          LastChangedAt,
    
          /* Associations */
          ///DMO/I_Travel_U
          _Agency,
          _Booking,
          _Currency,
          _Customer
    
    }
    
    

    Your MDE code should look like this:

    CDS
    Copy
    @Metadata.layer: #CORE
    annotate view Z_I_TRAVEL_R_XXX with
    {
    
    @UI           : {
          lineItem      : [{position: 15, importance: #HIGH}],
          selectionField: [{position: 15 }]
          }
    AgencyID;
    
    @UI           : {
          lineItem      : [{position: 20, importance: #HIGH}],
          selectionField: [{position: 20 }]
          }
    CustomerID;
    
    @UI           : {
          lineItem      : [{position: 10, importance: #HIGH}],
          selectionField: [{position: 10 }]
          }
    TravelID;
    
    @UI           : {
          lineItem      : [{position: 30, importance: #HIGH}],
          selectionField: [{position: 30 }]
          }
    BeginDate;
    
    @UI           : {
          lineItem      : [{position: 40, importance: #HIGH}],
          selectionField: [{position: 40 }]
          }
    EndDate;
    
    @UI           : {
          lineItem      : [{position: 50, importance: #HIGH}]
          }
    TotalPrice;
    
    @UI           : {
          lineItem      : [{position: 50, importance: #HIGH}]
          }
    Memo;
    
    @UI           : {
        lineItem      : [{position: 60, importance: #HIGH}],
        selectionField: [{position: 60 }]
        }
    Status;
    
    }
    
    
  • Step 15

    Where do you specify that your OData service is an OData version 2 service for UI?

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