Exercise: Implementing CRUD Operations in a TypeScript NestJS Application

In this exercise, you will learn how to implement CRUD operations in SAP Cloud SDK application. We will use the Mock Server instead of the actual SAP S/4HANA Cloud.

1. Checkout the branch tsnestjs_v3.0_crud in SAP Business Application Studio

   1. Open SAP Business Application Studio.

   2. Run the following commands in the terminal.

      Code snippet

      Copy code

      cd ~/projects/cloud-sdk-learning-journey
      git checkout tsnestjs_v3.0_crud

      Expand

      

2. Build and run the project.

   1. Run the application by executing the following commands in the terminal

      Code snippet

      Copy code

      cd cloudsdk_bp_ts
      npm i
      npm run build
      npm run start:dev

      Expand

      

3. Query the Business Partner API of SAP S/4HANA Cloud

   1. Open the requests.http file

   2. Click on Send Request in the requests.http file to submit the GET request for business partners

   3. Verify that the list of business partners are returned from the Mock Server. Note: If the Mock Server is not running, make sure to run the Mock Server on port 8081 by following the prerequisites at the top

   4. Click on the various Send Request in the requests.http file to submit GET, PUT, POST requests

   5. Verify that the response is correct for all the requests

      

4. Optional: Review code in the following source files

   1. Note

      Check out the SAP Cloud SDK documentation on Building an Address Manager Application with SAP Cloud SDK. https://sap.github.io/cloud-sdk/docs/js/tutorials/address-manager/change

      Code walk-through

      File name	Comments on code changes
      business-partner.controller.ts	Code logic is as follows... Annotate the class BusinessPartnerController with @Controller to mark it as a Controller class Create 5 methods getBusinessPartners, getBusinessPartnerById, createAddress, updateBusinessPartnerAddress, deleteBusinessPartnerAddress to handle the GET, GET/{id}, POST, PUT, DELETE requests Annotate each method with the respective @Get(), @Get('/:id'), @Post('/:businessPartnerId/address'), @Put('/:businessPartnerId/address/:addressId'), @Delete('/:businessPartnerId/address/:addressId') respectively Create an instance of the BusinessPartnerService class to handle each of the method implementation by passing in the required values
      business-partner.service.ts	Code logic is as follows... Implement logic for each of the methods in the Controller class Use the SAP Cloud SDK fluent API method chaining to provide additional parameters
      requests.http	Provides various HTTP requests that can be submitted to query the Business Partner API
      commands.txt	Provides various commands that can be run on the terminal

5. Optional: Manually create the project, without using the git branch, starting from the application you already created in the folder ~/projects/cloudsdk_bp_ts, within the previous exercise (Implementing resilience in a TypeScript NestJS application).

   1. Choose File → Open Folder... and open projects/cloudsdk_bp_ts.

   2. Create or update the following files in the table below

      File name	Type	Contents
      business-partner.controller.ts Path: ~/projects/cloudsdk_bp_ts/src/business-partner	Modified	Copy contents from here...
      business-partner.service.ts Path: ~/projects/cloudsdk_bp_ts/src/business-partner	Modified	Copy contents from here...

      

   3. Build and run the project in projects/cloudsdk_bp_ts in the same exact way you did in the previous steps with project in projects/cloud-sdk-learning-journey/cloudsdk_bp_ts.

      Code snippet

      Copy code

      cd ~/projects/cloudsdk_bp_ts
      npm i
      npm run build
      npm run start:dev

      Expand