RAP vs CAP (database-wise)

[bags26]

I’m seeking clarification on the pros and cons of using RAP and CAP strictly in terms of database usage. Based on my understanding, RAP utilizes the S/4HANA Cloud database within the ABAP environment, whereas CAP works with the S/4HANA Cloud database via the HANA DB Explorer.

In a recent internal discussion with SAP at our company, it was mentioned that the HANA database accessed through the HANA DB Explorer is more stable compared to the one used in the ABAP environment. This has caused some confusion, as I haven't been able to find clear information or articles to verify this.

Could you explain the difference between these databases?

Are there any advantages of one over the other?

Could you provide sample use cases where one would be preferred over the other?

Additionally, in terms of backup and restoration, is it possible to perform this for both environments?

[gregorw]

There is no "S/4HANA Cloud database". SAP S/4HANA Cloud is the Software as a Service ERP solution that is marketed by SAP as Cloud ERP. RAP is running on the ABAP Application Server and uses SAP HANA (the Database) when running on premise and SAP HANA Cloud when running in the Cloud (BTP ABAP Environement and S/4HANA Cloud 3-System Landscape). CAP can also use SAP HANA on prem when the XSA runtime is provided. In the BTP CAP can use SAP HANA Cloud but it is not the only option anymore. With @cap-js/postgres there is support for PostgreSQL. And there is even a project for cds-mysql.

The HANA Database Explorer is just a web based UI and is not that database.

[bags26]

So database for both programming model are residing in the same landscape (SAP HANA Cloud)? Means, same storage capacity, same computing power and data can be restored from back-up?

[gregorw]

But in the BTP ABAP Environment you don't have direct access to SAP HANA Cloud. Check https://help.sap.com/docs/btp/sap-business-technology-platform/backups?locale=en-US on what is possible regarding backup and restore.