This project demonstrates the integration to another CAP multitenant application using HANA Synonyms. The application providing the Books entity is mtxs-bookshop. The mtxs-bookshop defines HANA Roles (BOOKSHOP.hdbrole and BOOKSHOP_O.hdbrole) that allow this app to access the HANA Table MY_BOOKSHOP_BOOKS.
To achieve this functionality in a multitenant application we make use of a dynamically defined user provided service that gets its credentials from the service manager instance of the mtxs-bookshop app.
You might ask why to integrate two CAP applications in this way. Wouldn't an API based approach the better solution? I don't think so because as documented in Limitations and Feature Matrix of the CAP documentation on Consuming Services there is quite an overhead in using the API based approach. It would require a lot of additional code in the handlers.
cf create-service-key mtxs-reviews-db mtxs-reviews-db-key
cds bind -2 mtxs-reviews-db
Copy the entry created by the previous command from the .cdsrc-private.json file as the following command will replace it:
cds bind -2 mtxs-bookshop-db
Edit .cdsrc-private.json and paste the backup. Replace "name": "db" with "name": "mtxs-bookshop-db" for the "instance": "mtxs-bookshop-db".
To avoid issues with a wrong binding selection make sure to oversteer the default VCAP lookup by this configuration in .cdsrc-private.json:
"vcap": {
"name": "mtxs-reviews-db",
"label": false
}
"vcap": {
"name": mtxs-bookshop-db",
"label": false
}