unit4.md

HANDS-ON EXERCISE FOR WEEK 2 UNIT 4: CREATING CDS DATA MODEL PROJECTION

Previous exercise

Week 2 Unit 3: Creating the Core Data Services (CDS) Data Model

Introduction

In the present hands-on exercise, you will define the CDS data model projection for your travel app on top of the CDS data model defined in the previous exercise. With projection views, you can expose only those elements that are relevant for the specific service. You can de-normalize the underlying data model and also define fine-tuning such as virtual elements, value helps, search and UI semantics.

You can watch week 2 unit 4: Creating the CDS Data Model Projection on the openSAP platform.

Hints and Tips
Speed up the typing by making use of the Code Completion feature (shortcut Ctrl+Space) and the prepared code snippets provided. You can easily open an object with the shortcut Ctrl+Shift+A, format your source code using the Pretty Printer feature Shift+F1 and toggle the fullscreen of the editor using the shortcut Ctrl+M.

A great overview of ADT shortcuts can be found here: Useful ADT Shortcuts

Please note that the placeholder #### used in object names in the exercise description must be replaced with the suffix of your choice during the exercises. The suffix can contain a maximum of 4 characters (numbers and letters). The screenshots in this document have been taken with the suffix 1234 and system D20. Your system id will be TRL.

Please note that the ADT dialogs and views may change in the future due to software updates.

Follow the instructions below.

Step 1. Create the Travel Projection View

First, create the Travel BO projection view (aka consumption view) ZC_RAP_Travel_#### (where #### is your chosen suffix) for the Travel entity.

1. Right-click on your travel BO view (aka interface view) ZI_RAP_Travel_#### and choose New Data Definition from the context menu.

   

2. Maintain ZC_RAP_Travel_#### as name and a meaningful description (e.g. Travel BO projection view) in the creation wizard and choose Next > to continue.
   The project, the package and the referenced object have been automatically assigned in the creation wizard.

   Please note
   In this course, we will follow the naming convention of the Virtual Data Model (VDM) of the SAP S/4HANA where the name of interface or BO views begins with <namespace>I (e.g ZI_) and the name of consumption or projection views begins with the namespace followed by <namespace>C (e.g. ZC_).

   

3. Assign a transport request and choose Next >.

   

4. Choose the Define Projection View template from the list and then choose Finish.

   

   The new data definition appears in the editor.

   

   Short Explanation:
   The travel BO view is specified as projection view and all view elements have been automatically inserted in the projection list between the curly brackets.

5. Replace the travel data definition in the editor with the code snippet provided below and replace all occurrences of #### with your chosen suffix. You can make use of the Replace All feature (Ctrl+F) in ADT for the purpose.

   Save the changes, but DO NOT yet activate the travel BO projection view.

   You can make use of the Source Code Formatter (Shift+1) to format the source code.

    @EndUserText.label: 'Travel BO projection view'
    @AccessControl.authorizationCheck: #CHECK
    @Search.searchable: true
    @Metadata.allowExtensions: true
   
    define root view entity ZC_RAP_Travel_####
      as projection on ZI_RAP_Travel_#### as Travel
    {
      key TravelUUID,
          @Search.defaultSearchElement: true
          TravelID,
          @Consumption.valueHelpDefinition: [{ entity: { name: '/DMO/I_Agency', element: 'AgencyID'} }]
          @ObjectModel.text.element: ['AgencyName']
          @Search.defaultSearchElement: true
          AgencyID,
          _Agency.Name       as AgencyName,
          @Consumption.valueHelpDefinition: [{ entity: { name: '/DMO/I_Customer', element: 'CustomerID'} }]
          @ObjectModel.text.element: ['CustomerName']
          @Search.defaultSearchElement: true
          CustomerID,
          _Customer.LastName as CustomerName,
          BeginDate,
          EndDate,
          @Semantics.amount.currencyCode: 'CurrencyCode'
          BookingFee,
          @Semantics.amount.currencyCode: 'CurrencyCode'
          TotalPrice,
          @Consumption.valueHelpDefinition: [{ entity: { name: 'I_Currency', element: 'Currency'} }]
          CurrencyCode,
          Description,
          TravelStatus,
          LastChangedAt,
          LocalLastChangedAt,
   
          /* Associations */
          _Agency,
          _Booking : redirected to composition child ZC_RAP_Booking_####,
          _Currency,
          _Customer   
    }
    

   The data definition should look as follows.

   

   Short explanation: What has changed?

   • The alias Travel is specified for the projected view
   • The keyword root is specified in the DEFINE statement to specify the projected Travel BO as root node.
   • The view annotations @Metadata.allowedExtension is specified before the DEFINE statement to allow the projection view to be enhanced with separate metadata extensions
   • The view annotations @Search.Searchable is specified before the DEFINE statement to allow the projection view to enable the full-text (aka freestyle) search.
   • The freestyle search is enabled for the view elements TravelID, AgencyID and CustomerID using the annotation @Search.DefaultSearchElement.
   • The view elements AgencyName from the association _Agency and CustomerName from the association _Customer have been added to the projection list. They are specified as textual description for the view elements AgencyID and CustomerID respectively using the @ObjectModel.text.element annotation.
   • Value helps are specified for the view elements AgencyID, CustomerID, and CurrencyCode using the annotation @Consumption.valueHelpDefinition. The name of the target CDS entity that acts as a value help provider and the name of its element that is linked to the local element have to be specified.
   • The view element CurrencyCode is specified as the reference field for the currency fields BookingFee and TotalPrice using the @Semantics.amount.currencyCode annotations.
   • The view elements CreatedBy, CreatedAt and LastChangedBy have been removed from the projection list because they only have an are administrative function and will be of no use in our scenario. The view elements LastChangedAt and LocalLastChangedAt remain in the projection list because they will be used for the transactional enablement of Your Travel List Report App in week 3 – especially for the implementation of the optimistic lock.
   • associations have been exposed in the projection list
   • association to the booking BO child node (_Booking) has been redirected to the appropriate Booking BO projection view using the redirected to composition child statement.

   An error is currently displayed for this statement, because the specified Booking BO projection view ZC_RAP_Booking_#### does not yet exist.

Step 2. Create the Booking Projection View

Now, you will create the missing Booking BO projection view (aka consumption view) ZC_RAP_BOOKING_#### for the Booking entity - where #### is your chosen suffix.

1. Right-click on your Booking BO view (aka interface view) ZI_RAP_BOOKING_#### and choose New Data Definition from the context menu.

   

2. Maintain ZC_RAP_BOOKING_#### as name and a meaningful description (e.g. Booking BO projection view) in the creation wizard and choose Next > to continue.
   The project, the package and the referenced object have been automatically assigned in the creation wizard.

   

3. Assign a transport request and choose Next >.

   

4. Choose the Define Projection View template from the list and then choose Finish.

   

   The new data definition appears in the editor.

   

   Short Explanation: The booking BO view is specified as projection view and all view elements have been automatically inserted in the projection list between the curly brackets.

5. Replace the booking data definition in the editor with the code snippet provided below and replace all occurrences of #### with your chosen suffix. You can make use of the Replace All feature (Ctrl+F) in ADT for the purpose.

   Save the changes, but DO NOT yet activate the booking BO projection view.

   You can make use of the Source Code Formatter (Shift+1) to format the source code.

    @EndUserText.label: 'Booking BO projection view'
    @AccessControl.authorizationCheck: #CHECK
    @Search.searchable: true
    @Metadata.allowExtensions: true
   
    define view entity ZC_RAP_Booking_####
      as projection on ZI_RAP_Booking_#### as Booking
    {
      key BookingUUID,
          TravelUUID,
          @Search.defaultSearchElement: true
          BookingID,
          BookingDate,
          @Consumption.valueHelpDefinition: [{ entity : {name: '/DMO/I_Customer', element: 'CustomerID'  } }]
          @ObjectModel.text.element: ['CustomerName']
          @Search.defaultSearchElement: true
          CustomerID,
          _Customer.LastName as CustomerName,
          @Consumption.valueHelpDefinition: [{entity: {name: '/DMO/I_Carrier', element: 'AirlineID' }}]
          @ObjectModel.text.element: ['CarrierName']
          CarrierID,
          _Carrier.Name      as CarrierName,
          @Consumption.valueHelpDefinition: [ {entity: {name: '/DMO/I_Flight', element: 'ConnectionID'},
                                               additionalBinding: [ { localElement: 'CarrierID',    element: 'AirlineID' },
                                                                    { localElement: 'FlightDate',   element: 'FlightDate',   usage: #RESULT},
                                                                    { localElement: 'FlightPrice',  element: 'Price',        usage: #RESULT },
                                                                    { localElement: 'CurrencyCode', element: 'CurrencyCode', usage: #RESULT } ] } ]
          ConnectionID,
          FlightDate,
          @Semantics.amount.currencyCode: 'CurrencyCode'
          FlightPrice,
          @Consumption.valueHelpDefinition: [{entity: {name: 'I_Currency', element: 'Currency' }}]
          CurrencyCode,
          LocalLastChangedAt,
   
          /* associations */
          _Travel : redirected to parent ZC_RAP_Travel_####,
          _Customer,
          _Carrier,
          _Connection,
          _Flight
    }
    

   The data definition now looks as follows.

   

   Short explanation: What has changed?

   • The alias Booking is specified for the projected view
   • The view annotations @Metadata.allowedExtension is specified before the DEFINE statement to allow the projection view to be enhanced with separate metadata extensions
   • The view annotations @Search.Searchable is specified before the DEFINE statement to allow the projection view to enable the full-text (aka freestyle) search.
   • The view columns BookingID and CustomerID are enabled for freestyle search.
     The view elements CustomerName and CarrierName from the associations _Customer_ and _Carrier respectively have been added to the projection list.
     They are specified as textual description for the view elements CustomerID and CarrierID respectively using the annotation @ObjectModel.text.element.
   • Value helps are specified for the view elements CustomerID, CarrierID, ConnectionID and CurrencyCode using the annotation @Consumption.valueHelpDefinition.
     In the value help definition of the element ConnectionID, an additional binding condition is defined for returning values from the selected value help record for the local view elements CarrierID, FlightDate, FlightPrice and Currency.
   • The view element CurrencyCode is specified as reference field for the currency field FlightPrice.
   • The view elements CreatedBy and LastChangedBy have been removed from the projection list because they only have an administrative function and will be of no use in our scenario. The view element LocalLastChangedAt remains in the projection list because it will be used for the transactional enablement of Your Travel List Report App in week 3 – especially for the implementation of the optimistic lock.
   • All associations have been exposed in the projection list.
   • The association to the travel BO parent node has been redirected to the appropriate Travel BO projection view using the redirected to parent statement.

Step 3. Activate the CDS Data Model Projection & Run the Data Preview

To avoid error during the activation, both new CDS interface views – i.e. Travel view and Booking view – must be activated together for the first time.

1. Choose Activate All or use the shortcut Ctrl+Shift+F3.
   Select both CDS views ZC_RAP_TRAVEL_#### and ZC_RAP_BOOKING_#### on the appearing dialog, and choose Activate.

   

   Your projected CDS data model consisting of the Travel BO projection view and the Booking BO projection view are now activated, but warnings are displayed in the Problems view. The reason behind this is that the authority check is allowed for these CDS views (using the view annotation @AccessControl.authorizationCheck: #CHECK), but no CDS access control is yet defined for them.

   You will work on this in unit 7 of week 2 where you will implement a basic CDS access control.

   

2. To run the Data Preview, choose one of the CDS views - i.e. ZC_RAP_TRAVEL_#### or ZC_RAP_BOOKING_#### - in the Project Explorer or open it in the editor, and press F8.

   The data preview will open in the editor area.

   

   

Summary

You have completed the exercise!
In this unit, you have learned how to define a CDS data model projection for business objects.

Solution

Find the source code of the created CDS data definitions (consumption views) in the /week2/sources folder:

• W2U4_DDLS_ZC_RAP_TRAVEL_####
• W2U4_DDLS_ZC_RAP_BOOKING_####

Next exercise

Week 2 Unit 5: Enriching the Projected Data Model with UI Metadata