A netizen asked: If you can use OData to directly communicate with the SAP system, what is the significance of platforms such as BTP and CPI?

A friend asked:

External SaaS applications access the SAP standard interface through ODATA API, and can directly initiate access from the local application, without resorting to PI or BTP platforms, right? In this case, what are the advantages of building applications through BTP or CPI compared to building applications directly on third-party platforms? Is it because these two platforms have more functions related to process design and similar extension plug-ins (without reinventing wheels) in addition to obtaining data, and can they be released to the SAP application market? That is, if I don’t need these plug-ins, I can bypass these platforms before the application market is released.

Regarding the integration between SAP and third-party systems, I wrote a short article: Introduction to some scenarios of SAP S/4HANA Cloud system integration

Both SAP On-Premises and SAP Cloud products can expose their business in the form of OData services for third-party system integration.

SAP Cloud products, to be more precise, SAP Public Cloud products, its OData services can be accessed directly through the public network. In theory, in third-party applications, you can directly use Java, C#, nodejs, Python or other programming languages and call the OData API. In the scenario of integration with SAP Public Cloud, third-party applications can be deployed on SAP BTP or on any other server, such as a local server, or Tencent Cloud, Alibaba Cloud, and so on.

In contrast to the OData API exposed by SAP On-Premises, because SAP On-Premises is usually deployed on the corporate intranet, its OData API cannot be directly accessed by third-party applications. It needs to use the SAP Cloud Connector to achieve intranet and extranet traversal, as shown in the middle of the figure below. Secure Tunnel. In this scenario, SAP BTP is a must.

In addition to combining with SAP Cloud Connector to enable third-party applications to access the enterprise intranet On-Premises system, SAP BTP also provides many out-of-the-box services on its Service Market Place, including application-level Business Service, which is also biased. Technical Service at the underlying infrastructure (infrastructure) level. After third-party applications are deployed on SAP BTP, these services can be consumed to avoid duplication of wheels.

Of course, if third-party applications do not need to connect to the SAP On-Premises system, nor do they need to use the services of the SAP BTP service market, then in theory, there is no technical problem if third-party applications are not deployed on SAP BTP.

Let's talk about CPI. The third-party system integrates with the SAP system by synchronizing the OData API, which is simple to implement and low in cost. As SAP CPI is a middleware between a third-party system and the SAP product to be integrated, the two methods have their own advantages and disadvantages. Using the OData API to directly connect to the SAP system, we can understand it as a message communication mechanism in a broad sense. This mechanism lacks message persistence, message monitoring, and retry mechanism after message sending errors. When the exchange scenario between a third-party system and SAP products becomes more complex, as shown in the figure below, the external system is integrated with the SAP S/4HANA service scenario, and the third-party application will actively send two messages to S/4HANA. And receive an asynchronous message from SAP S/4HANA. Only when the two sending and receiving operations are completed, a scene is considered to be completely processed. If the OData API sending mechanism is adopted, measures such as error handling and boundary condition control in this scenario need to be implemented in third-party applications, and the development complexity is relatively high. These are the strengths and uses of SAP CPI as middleware.

In summary, the third-party system is integrated with the SAP system. Whether to choose SAP BTP or CPI depends on the specific scenarios and implementation complexity required for the integration.

More original articles by Jerry, all in: "Wang Zixi":