Create a Data Model and Expose It as a Service

1. Enter the Dev Space you created in Set Up SAP Business Application Studio for Low-Code Development in the Trial Environment.

2. If no project exists in a dev space the Create Project dialog box opens. Enter the Project Name, for example, CapitalExpenditures, and click Create.

   

   If a project already exists in your dev space, you can create an additional project by selecting Project -> Create in the Home tab.

   

3. Wait for the homepage of SAP Business Application Studio for low-code development to load with the new project.

   Wait for the “We have finished installing all tools and templates for you, enjoy your work!” notification.

   Loading SAP Business Application Studio for low-code development may take some time, especially if it’s the first time in a day.

   

   Close the notification icon at the bottom of the screen (optional).

1. From the homepage, click the + of the Data Models tile to add a data model to your project.

   

2. Provide an Entity Name for the entity, for example, Capex.

   

3. Click the + to add a property to the Capex entity.

   

4. Select the following:

   Step	Parameter	Value
   A	Property Name	description
   B	Property Type	String (default)
   C	Key	Leave unchecked (default)
   D	Null	Yes (default)
   E	Arrayed	Leave unchecked (default)
   F	Max Length	Leave empty
   G	Default Value	Leave empty (default)

   

5. Add the following property (click +). When done with adding the properties choose Create.

   Step	Parameter	Value
   A	Property Name	total_cost
   B	Property Type	Integer
   C	Key	Leave unchecked (default)
   D	Null	Yes (default)
   E	Arrayed	Leave unchecked (default)
   F	Default Value	Leave empty (default)

   

   The Capex entity appears in the Data Model Editor tab with a default ID property.

   

6. To add another data model to your project click the Add Entity button in the Data Model Editor tab.

   

   A new entity appears in the Data Model Editor tab.

   To edit the entity, click the entity’s header and choose the Edit Entity icon.

   

7. Provide an Entity Name for the entity, for example, Contractors.

   

8. Change the Property Name of the ID property to contractor, and its Property Type to Integer.

   

9. Add the following property to the Contractors entity, and choose Update.

   Step	Parameter	Value
   A	Property Name	name
   B	Property Type	String (default)
   C	Key	Leave unchecked (default)
   D	Null	Yes (default)
   E	Arrayed	Leave unchecked (default)
   F	Max Length	Leave empty
   G	Default Value	Leave empty (default)

   

   The Contractors entity appears in the Data Model Editor.

1. With relationships you can connect your entities. To do so, select the Capex entity, choose the Add Relationship icon, and select the Contractors entity to add a relationship to the Contractors entity.

   
   

2. Select the following, and choose Create.

   Step	Parameter	Value
   A	Relationship Type	Association (default)
   B	Multiplicity	To-One (default)
   C	Key Property	No (default)
   D	Property Name	contractor
   E	Target Entity	CapitalExpenditures.Contractors (default)
   F	Backlink Property	Leave empty (default)

   

3. You can re-arrange the entities on the canvas by clicking the Auto Layout icon to improve the data model visualization. In addition, you can also manually drag the entities over the canvas.

   

1. Access the Home tab.

   

2. Click the + of the Services tile to add a service through which data from the data model can be accessed.

   

3. Define the following for your new service, and choose Create.

   Step	Parameter	Value
   A	Name	Capex
   B	Namespace	CapitalExpendituresService (default)
   C	Type	CapitalExpenditures.Capex
   D	<all properties>	Leave checked (default)
   E	ID	Leave checked (default)
   F	description	Leave checked (default)
   G	total_cost	Leave checked (default)
   H	contractor	Leave checked (default)

   

   The Capex service appears in the Service Editor tab.

4. To add another new service to your project click the Add Entity button in the Service Editor tab, define the following, and choose Create.

   Step	Parameter	Value
   A	Name	Contractors
   B	Namespace	CapitalExpendituresService (default)
   C	Type	CapitalExpenditures.Contractors
   D	<all properties>	Leave checked (default)
   E	contractor	Leave checked (default)
   F	name	Leave checked (default)

   
   

   The Contractors service is added to the Service Editor, with association to the Capex service.

   

5. Select the Capex service (which gets highlighted with a blue rectangle indication), and check the Draft Editing property.

   A draft is an interim version of a business entity that has not yet been explicitly saved as an active version. This allows users to pause, for example when being interrupted, and continue later on. For more information visit SAP Fiori Design Guidelines - Draft Handling.

   

6. You can re-arrange the entities on the canvas by clicking the Auto Layout icon to improve the service visualization. In addition, you can also manually drag the entities over the canvas.

   

7. Access the Home tab. You can see that both the services are added to the Services tile.

   

It is a common practice in software development to test run any change to an app as soon as possible. Prior to having the services defined, you were not able to test the app. Since now you have defined the services, you can test them.

1. Choose the Preview option from the homepage, and select Run CapitalExpenditures-1.

   Troubleshooting: CapitalExpenditures is the name you have previously chosen for your project. If you have chosen a different name, this name will be displayed, for example, Run DifferentName-1.

   

2. The project preview page appears in a new tab with the links which allow you to test the service definition, access data exposed by the service, and more.

   

3. In the preview page on the right side under Services choose the metadata link to view the service’s XML. Close the XML file.

   

4. Also in the preview page on the right side under Services select the button view as code next to Capex or Contractors to view the data from the respective service.

   

   Here, the value appears as an empty list since the data model is empty.

To test that the service works well, that is, returns data when it is available in the data model, let’s add sample data to your project. Sample data is a powerful tool as it allows you to (1) develop an app with no connectivity to a data source; (2) Debug your app.

1. Go back to the browser tab with SAP Business Application Studio for low-code development, and click the + of the Sample Data tile.

   

2. Select Contractors, select Create, and press Add.

   

3. In the sample data editor add 4 rows.

   

4. Update the sample data as follows:

   

5. Access the Home tab, and click the + of the Sample Data tile.

   

6. Select Capex, select Create, and press Add.

   

7. In the sample data editor add 3 rows, and update the DESCRIPTION and CONTRACTOR columns as follows:

   

8. Access the Home tab. You can see that the sample data is added to the Sample Data tile.

   

9. Go back to the project preview browser tab, and select the button view as code next to Capex or Contractors. You can view the sample data you have added.