Lets take a look at the architecture of the demo application:
products service: handles querying products from the database and returning them to the frontendorders service: handles validating and creating ordersorder history service: handles querying a customer's order historypayments service: handles processing orders for paymentapi gateway: unifies the services under a single endpointmongodb/ postgresql: serves as the write-optimized database for storing orders, order history, products, etc.
You don't need to use MongoDB/ Postgresql as your write-optimized database in the demo application; you can use other prisma supported databases as well. This is just an example.