Build OData Queries with the SAP Cloud SDK's Virtual Data Model

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Build OData Queries with the SAP Cloud SDK's Virtual Data Model

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Build OData Queries with the SAP Cloud SDK's Virtual Data Model

2019-12-10

Intermediate

30 min.

Build OData queries with the SAP Cloud SDK's virtual data model to build an address manager application.

You will learn

What the OData Virtual Data Model for SAP S/4HANA Cloud is
How to use the Virtual Data Model to query the business partner service
How to expose the business partners in an Express.js application

Prerequisites

Have Node.js and npm installed on your machine.
Have access to an SAP S/4HANA Cloud system or the SAP API Business Hub Sandbox, or use the Business Partner Mock Service.
Basic knowledge of OData is recommended, but not required.

The goal of this tutorial group is to show you how to implement a JavaScript application that allows you to manage the addresses of business partners. This application will be using Express.js and the SAP Cloud SDK for JavaScript. In this tutorial, we introduce the SAP Cloud SDK’s OData Virtual Data Model and teach you how to use it to query business partners from an SAP S/4HANA Cloud system.

Step 1: What is the SAP Cloud SDK's Virtual Data Model?

Most of the services exposed by SAP S/4HANA Cloud and On-Premise are OData services. OData is a RESTful API protocol that has two key features: First, each services is described by a metadata document that lists all entities, their properties and relations, and which operations can be executed on them. Second, OData defines a set of SQL-like operators that allow constructing powerful queries.

However, building requests by hand can be tedious and error-prone. It’s easy to mistype the name of an entity or a property, which will make the request fail. Furthermore, you have to continuously cross-check with the service’s metadata to look up the spelling and types of entities and properties.

The Virtual Data Model is a set of API clients that are generated from a service’s metadata. Every entity and their properties are represented by concrete objects. This allows you to build requests in a fluent, type-safe and discoverable manner.

Done

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Step 2: Set up your application

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This tutorial and the following ones in this group are based on the SAP Cloud SDK’s TypeScript project scaffolding. We have described how to set it up in a previous tutorial. Go ahead and download the project scaffolding as starting point for these tutorials.

For each OData service in SAP S/4HANA Cloud, there is a corresponding npm package in the SAP Cloud SDK. You can find an overview of all packages here. All of the VDM packages are prefixed with @sap/cloud-sdk-vdm. The package for the business partner service can be installed by executing the following command on your command line:

npm install @sap/cloud-sdk-vdm-business-partner-service

Starting with version 1.4.0 of the SAP Cloud SDK for JavaScript, you can also use our generator for your own custom OData services.

Done

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Step 3: Add an API endpoint

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Start by creating a file called business-partners-route.ts in the src folder of the project. Copy the following code into the file:

import { Request, Response } from 'express';

export function businessPartnersRoute(req: Request, res: Response) {
  res.status(200).send('Nothing to see yet...');
}

The function businessPartnersRoute is the function that will handle requests to the API endpoint that we create. Every function in Express.js that handles a request takes two parameters: the Request object and the Response object (though we don’t need the Request for now).

Now you need to instruct the Express.js router to delegate incoming requests to /business-partners to the businessPartnersRoute function. To do so, open the application.ts file, import your function and add a route to the router:

import { businessPartnersRoute } from './business-partners-route';

// ...

private routes(): void {
  const router = express.Router();

  router.get('/', indexRoute);
  router.get('/hello', helloWorld);
  // add the following line
  router.get('/business-partners', businessPartnersRoute);
  this.app.use('/', router);
}

Now you can start your app using npm run start:local or npm run serve-debug. When the server is running, you should see Express server listening on port 8080 on your command line. Open http://localhost:8080/business-partners and you should see 'Nothing to see yet...'.

Start by creating a file called business-partners-route.js in the src folder of the project. Copy the following code into the file:

function businessPartnersRoute(req, res) {
  res.status(200).send('Nothing to see yet...');
}

module.exports.businessPartnersRoute = businessPartnersRoute;

Now you need to instruct the Express.js router to delegate incoming requests to /business-partners to the businessPartnersRoute function. To do so, open the application.js file, import your function and add a route to the router:

const { businessPartnersRoute } = require('./business-partners-route');

// ...

private routes() {
  const router = express.Router();

  router.get('/', indexRoute);
  router.get('/hello', helloWorld);
  // add the following line
  router.get('/business-partners', businessPartnersRoute);
  this.app.use('/', router);
}

Done

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Step 4: Query the business partner service

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Every request you can do with the VDM follows a common pattern. You start with the entity that you want to perform a request on, in this case BusinessPartner. To build a request, call the requestBuilder function. Next, you can select which request to build. OData, as RESTful API protocol, follows the CRUD model: Create, Read, Update, Delete. For reading, we differentiate between querying the service, where you get all available entities if you don’t specifically restrict the result set, and retrieving a specific entity by its key. The respective functions are called getAll and getByKey. For the remaining requests, the functions are simply called create, update and delete. When you type BusinessPartner.requestBuilder()., your IDE should show which operations are available on the respective entity. For example, it is not possible to delete a business partner via the business partner service. Therefore, the VDM will not offer a delete function.

Following this pattern, update your code as shown below (mind the updated import):

import { Request, Response } from 'express';
import { BusinessPartner } from '@sap/cloud-sdk-vdm-business-partner-service';

export function businessPartnersRoute(req: Request, res: Response) {
  res.status(200).send('Nothing to see yet...');
}

function getAllBusinessPartners(): Promise<BusinessPartner[]> {
  return BusinessPartner.requestBuilder()
    .getAll();
}

Requests can be executed with the execute function. To do this, the request builder needs to know where to send this request, in the form of a Destination. In this tutorial, we will provide this information directly to the execute function. We have described how to integrate with SAP Cloud Platform’s Destination Service in this tutorial. Every destination requires a URL. Note, that we do not need the full URL to the service, but only the host of the system. Suppose, you have an SAP S/4HANA Cloud system running under https://my.s4hana.ondemand.com/, you can pass that information directly to the request builder like this:

import { BusinessPartner } from '@sap/cloud-sdk-vdm-business-partner-service';

function getAllBusinessPartners(): Promise<BusinessPartner[]> {
  return BusinessPartner.requestBuilder()
    .getAll()
    .execute({
      url: 'https://my.s4hana.ondemand.com/'
    });
}

Following this pattern, update your code as shown below (mind the updated require):

const { BusinessPartner } = require('@sap/cloud-sdk-vdm-business-partner-service');

function businessPartnersRoute(req, res) {
  res.status(200).send('Nothing to see yet...');
}

module.exports.businessPartnersRoute = businessPartnersRoute;

function getAllBusinessPartners() {
  return BusinessPartner.requestBuilder()
    .getAll();
}

const { BusinessPartner } = require('@sap/cloud-sdk-vdm-business-partner-service');

function getAllBusinessPartners() {
  return BusinessPartner.requestBuilder()
    .getAll()
    .execute({
      url: 'https://my.s4hana.ondemand.com/'
    });
}

Done

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Step 5: Add authentication to the request

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Typically, you will need to authenticate yourself against a system in order to successfully execute a request. If you have a technical user for your system, you can pass the credentials like this:

import { BusinessPartner } from '@sap/cloud-sdk-vdm-business-partner-service';

function getAllBusinessPartners(): Promise<BusinessPartner[]> {
  return BusinessPartner.requestBuilder()
    .getAll()
    .execute({
      url: 'https://my.s4hana.ondemand.com/',
      username: "USERNAME",
      password: "PASSWORD"
    });
}

Alternatively, if you want to use the sandbox of the SAP API Business Hub, you will need to provide an APIKey. withCustomHeaders allows you to add custom HTTP headers to the request. You can pass your API key like this:

import { BusinessPartner } from '@sap/cloud-sdk-vdm-business-partner-service';

function getAllBusinessPartners(): Promise<BusinessPartner[]> {
  return BusinessPartner.requestBuilder()
    .getAll()
    .withCustomHeaders({
      APIKey: 'YOUR-API-KEY'
    })
    .execute({
      url: 'https://sandbox.api.sap.com/s4hanacloud/'
    });
}

Typically, you will need to authenticate yourself against a system in order to successfully execute a request. If you have a technical user for your system, you can pass the credentials like this:

const { BusinessPartner } = require('@sap/cloud-sdk-vdm-business-partner-service');

function getAllBusinessPartners() {
  return BusinessPartner.requestBuilder()
    .getAll()
    .execute({
      url: 'https://my.s4hana.ondemand.com/',
      username: "USERNAME",
      password: "PASSWORD"
    });
}

const { BusinessPartner } = require('@sap/cloud-sdk-vdm-business-partner-service');

function getAllBusinessPartners() {
  return BusinessPartner.requestBuilder()
    .getAll()
    .withCustomHeaders({
      APIKey: 'YOUR-API-KEY'
    })
    .execute({
      url: 'https://sandbox.api.sap.com/s4hanacloud/'
    });
}

Done

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Step 6: Add select to the request

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Like SQL, OData allows to only select specific properties of an entity. For our address manager, we only want to know the ID, the first name and the last name of a business partner. Add a select statement to your request like this:

import { BusinessPartner } from '@sap/cloud-sdk-vdm-business-partner-service';

function getAllBusinessPartners(): Promise<BusinessPartner[]> {
  return BusinessPartner.requestBuilder()
    .getAll()
    .select(
      BusinessPartner.BUSINESS_PARTNER,
      BusinessPartner.FIRST_NAME,
      BusinessPartner.LAST_NAME
    )
    .execute({
      url: 'https://my.s4hana.ondemand.com/'
    });
}

const { BusinessPartner } = require('@sap/cloud-sdk-vdm-business-partner-service');

function getAllBusinessPartners() {
  return BusinessPartner.requestBuilder()
    .getAll()
    .select(
      BusinessPartner.BUSINESS_PARTNER,
      BusinessPartner.FIRST_NAME,
      BusinessPartner.LAST_NAME
    )
    .execute({
      url: 'https://my.s4hana.ondemand.com/'
    });
}

As you can see, each property we select is represented by an object on the BusinessPartner entity. If you type BusinessPartner. in your IDE, you will see all the properties the can be selected on that entity. This saves you from having to look up the properties in the metadata, and prevents errors due to mistyping.

Done

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Step 7: Add a filter to the request

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Business partners can either be natural persons or legal persons (e.g. organizations or companies). For the address manager, we only want the addresses of natural persons. Therefore, we need to a filter to our request. Modify your code like this:

import { BusinessPartner } from '@sap/cloud-sdk-vdm-business-partner-service';

function getAllBusinessPartners(): Promise<BusinessPartner[]> {
  return BusinessPartner.requestBuilder()
    .getAll()
    .select(
      BusinessPartner.BUSINESS_PARTNER,
      BusinessPartner.FIRST_NAME,
      BusinessPartner.LAST_NAME
    )
    .filter(
      BusinessPartner.BUSINESS_PARTNER_CATEGORY.equals('1')
    )
    .execute({
      url: 'https://my.s4hana.ondemand.com/'
    });
}

const { BusinessPartner } = require('@sap/cloud-sdk-vdm-business-partner-service');

function getAllBusinessPartners() {
  return BusinessPartner.requestBuilder()
    .getAll()
    .select(
      BusinessPartner.BUSINESS_PARTNER,
      BusinessPartner.FIRST_NAME,
      BusinessPartner.LAST_NAME
    )
    .filter(
      BusinessPartner.BUSINESS_PARTNER_CATEGORY.equals('1')
    )
    .execute({
      url: 'https://my.s4hana.ondemand.com/'
    });
}

As for select, you can use the properties of the BusinessPartner entity directly for filtering. Each property offers a set of functions for constructing filters. Every property has the equals and nonEquals function. Depending on that type of the property, there can be additional functions like greaterThan or greaterOrEqual. Also, since we know the type of the property, the VDM will prevent your from passing values of the wrong type. For example, BusinessPartner.FIRST_NAME.equals(1) would not compile (in pure JavaScript the code would only fail at runtime, but most editors will still raise a warning for the type mismatch).

Done

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Step 8: Optional: Complex filters

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While this not required for the address manager, it’s a good time to introduce complex filters. By default, multiple filter statements passed to the filter function will be combined with a logical AND. For example, the following code will only retrieve business partners that are natural persons and whose first name is not “John”:

import { BusinessPartner } from '@sap/cloud-sdk-vdm-business-partner-service';

function getAllBusinessPartners(): Promise<BusinessPartner[]> {
  return BusinessPartner.requestBuilder()
    .getAll()
    .select(
      BusinessPartner.BUSINESS_PARTNER,
      BusinessPartner.FIRST_NAME,
      BusinessPartner.LAST_NAME
    )
    .filter(
      BusinessPartner.BUSINESS_PARTNER_CATEGORY.equals('1'),
      BusinessPartner.FIRST_NAME.notEquals('John')
    )
    .execute({
      url: 'https://my.s4hana.ondemand.com/'
    });
}

However, suppose we also want to retrieve business partners if they have been created in 2019 or later. For such use cases, you can use the and and or functions.

import { and, or } from '@sap/cloud-sdk-core';
import { BusinessPartner } from '@sap/cloud-sdk-vdm-business-partner-service';
import * as moment from 'moment';

function getAllBusinessPartners(): Promise<BusinessPartner[]> {
  return BusinessPartner.requestBuilder()
    .getAll()
    .select(
      BusinessPartner.BUSINESS_PARTNER,
      BusinessPartner.FIRST_NAME,
      BusinessPartner.LAST_NAME
    )
    .filter(
      or(
        BusinessPartner.CREATION_DATE.greaterThan(moment('2019-01-01 00:00:00')),
        and(
          BusinessPartner.BUSINESS_PARTNER_CATEGORY.equals('1'),
          BusinessPartner.FIRST_NAME.notEquals('Joe')
        )
      )
    )
    .execute({
      url: 'https://my.s4hana.ondemand.com/'
    });
}

const { BusinessPartner } = require('@sap/cloud-sdk-vdm-business-partner-service');

function getAllBusinessPartners() {
  return BusinessPartner.requestBuilder()
    .getAll()
    .select(
      BusinessPartner.BUSINESS_PARTNER,
      BusinessPartner.FIRST_NAME,
      BusinessPartner.LAST_NAME
    )
    .filter(
      BusinessPartner.BUSINESS_PARTNER_CATEGORY.equals('1'),
      BusinessPartner.FIRST_NAME.notEquals('John')
    )
    .execute({
      url: 'https://my.s4hana.ondemand.com/'
    });
}

However, suppose we also want to retrieve business partners if they have been created in 2019 or later. For such use cases, you can use the and and or functions.

const { and, or } = require('@sap/cloud-sdk-core');
const { BusinessPartner } = require('@sap/cloud-sdk-vdm-business-partner-service');
const moment = require('moment');


function getAllBusinessPartners() {
  return BusinessPartner.requestBuilder()
    .getAll()
    .select(
      BusinessPartner.BUSINESS_PARTNER,
      BusinessPartner.FIRST_NAME,
      BusinessPartner.LAST_NAME
    )
    .filter(
      or(
        BusinessPartner.CREATION_DATE.greaterThan(moment('2019-01-01 00:00:00')),
        and(
          BusinessPartner.BUSINESS_PARTNER_CATEGORY.equals('1'),
          BusinessPartner.FIRST_NAME.notEquals('Joe')
        )
      )
    )
    .execute({
      url: 'https://my.s4hana.ondemand.com/'
    });
}

Done

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Step 9: Optional: Custom fields

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The OData services in SAP S/4HANA Cloud can be extended by so-called custom fields. A custom field is any property that is not present in the default metadata of a service. Therefore, custom fields are of not “known” to the VDM. However, we still offer the same level of convenience for select and filter.

Suppose you have extended your business partner entity by a field that stores which user has last checked the addresses. You could use this field for selecting and filtering like this:

import { BusinessPartner } from '@sap/cloud-sdk-vdm-business-partner-service';

const ADDR_LAST_CHECKED_BY: CustomField<BusinessPartner> = BusinessPartner.customField('YY1_AddrLastCheckedBy_bus');

BusinessPartner.requestBuilder()
  .getAll()
  .select(
    BusinessPartner.FIRST_NAME,
    BusinessPartner.LAST_NAME,
    ADDR_LAST_CHECKED_BY
  )
  .filter(ADDR_LAST_CHECKED_BY.notEquals('John_Doe'))
  .execute({
    url: 'https://my.s4hana.ondemand.com/'
  });

Every entity offers a set of functions to interact with custom fields. You can get the value of a specific field using the getCustomField function. Alternatively, you can also get an object holding all fields using getCustomFields.

import { BusinessPartner } from '@sap/cloud-sdk-vdm-business-partner-service';

// pre-existing businessPartner

const fieldValue: any = businessPartner.getCustomField('YY1_AddrLastCheckedBy_bus');
const allCustomFields: { [key: string]: any } = businessPartner.getCustomFields();

Note, that the values will always be typed with any. The type of a custom field can be any JSON primitive, i.e. boolean, string, number and null. If there is no custom field with the given name, getCustomField will return undefined. You can check whether a custom field with a given name exists using the hasCustomField function. You can set the value for a custom field using the setCustomField function:

import { BusinessPartner } from '@sap/cloud-sdk-vdm-business-partner-service';

// pre-existing businessPartner

businessPartner.setCustomField('YY1_AddrLastCheckedBy_bus', 'John_Doe');

const { BusinessPartner } = require('@sap/cloud-sdk-vdm-business-partner-service');

const ADDR_LAST_CHECKED_BY = BusinessPartner.customField('YY1_AddrLastCheckedBy_bus');

BusinessPartner.requestBuilder()
  .getAll()
  .select(
    BusinessPartner.FIRST_NAME,
    BusinessPartner.LAST_NAME,
    ADDR_LAST_CHECKED_BY
  )
  .filter(ADDR_LAST_CHECKED_BY.notEquals('John_Doe'))
  .execute({
    url: 'https://my.s4hana.ondemand.com/'
  });

const { BusinessPartner } = require('@sap/cloud-sdk-vdm-business-partner-service');

// pre-existing businessPartner

const fieldValue = businessPartner.getCustomField('YY1_AddrLastCheckedBy_bus');
const allCustomFields = businessPartner.getCustomFields();

const { BusinessPartner } = require('@sap/cloud-sdk-vdm-business-partner-service');

// pre-existing businessPartner

businessPartner.setCustomField('YY1_AddrLastCheckedBy_bus', 'John_Doe');

Note, that you cannot use a field name that already exists. For example, if you would try to use setCustomField('FirstName', 'Joe'), an error would be thrown, because the field FirstName already exists on the business partner entity.

Done

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Step 10: Wire everything up

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You’ve finished the implementation of getAllBusinessPartners! To make the result available to clients, you need to call the function in businessPartnersRoute and send the result to clients. Update business-partners-route.ts so that it looks like this:

import { Request, Response } from 'express';
import { BusinessPartner } from '@sap/cloud-sdk-vdm-business-partner-service';

export function businessPartnersRoute(req: Request, res: Response) {
  getAllBusinessPartners()
    .then(businessPartners => {
      res.status(200).send(businessPartners);
    })
    .catch(error => {
      res.status(500).send(error.message);
    })
}

function getAllBusinessPartners(): Promise<BusinessPartner[]> {
  return BusinessPartner.requestBuilder()
    .getAll()
    .select(
      BusinessPartner.BUSINESS_PARTNER,
      BusinessPartner.FIRST_NAME,
      BusinessPartner.LAST_NAME
    )
    .filter(
      BusinessPartner.BUSINESS_PARTNER_CATEGORY.equals('1')
    )
    .execute({
      url: 'https://my.s4hana.ondemand.com/'
    });
}

const { BusinessPartner } = require('@sap/cloud-sdk-vdm-business-partner-service');

function businessPartnersRoute(req, res) {
  getAllBusinessPartners()
    .then(businessPartners => {
      res.status(200).send(businessPartners);
    })
    .catch(error => {
      res.status(500).send(error.message);
    })
}

module.exports.businessPartnersRoute = businessPartnersRoute;

function getAllBusinessPartners() {
  return BusinessPartner.requestBuilder()
    .getAll()
    .select(
      BusinessPartner.BUSINESS_PARTNER,
      BusinessPartner.FIRST_NAME,
      BusinessPartner.LAST_NAME
    )
    .filter(
      BusinessPartner.BUSINESS_PARTNER_CATEGORY.equals('1')
    )
    .execute({
      url: 'https://my.s4hana.ondemand.com/'
    });
}

businessPartnersRoute now calls the getAllBusinessPartners, which returns a Promise. A Promise can have two result states. Either the execution of the wrapped function succeeded, or it failed.

The success case can be handled with the then function. This gives you access to the return value of the wrapped function, which is an array of business partners. res.status(200).send(businessPartners) sends a response to the client with HTTP status code 200 and the business partner array as body.

Similarly, the error case is handled with the catch function. Should an error by thrown, we respond with status code 500 and send the error message to the client.

Restart your server and open http://localhost:8080/business-partners. You should see a list of business partners!

Done

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Step 11: Test yourself

Which problems does the VDM solve compared to manually constructing OData requests? runtime-safety type-safety discoverability of properties discoverability of services

Write the command to install the SAP Cloud SDK's npm package for the SAP S/4HANA Cloud Business Partner Service.

Write the minimum necessary code to get all business partners from a system under 'https://my.cloud.erp.com' (assuming no authentication is necessary).

Next Steps

Navigate tutorial steps

Step 1: What is the SAP Cloud SDK's Virtual Data Model?
Step 2: Set up your application
Step 3: Add an API endpoint
Step 4: Query the business partner service
Step 5: Add authentication to the request
Step 6: Add select to the request
Step 7: Add a filter to the request
Step 8: Optional: Complex filters
Step 9: Optional: Custom fields
Step 10: Wire everything up
Step 11: Test yourself
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Build OData Queries with the SAP Cloud SDK's Virtual Data Model

Build OData Queries with the SAP Cloud SDK's Virtual Data Model

You will learn

Prerequisites

Next Steps

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