About 90% of our GraphQL API passes through Prisma. We have a master API that talks to many different microservices to process data and so-on, but all the data ultimately ends up residing in our Postgres DB. One of the nice things about Prisma is that it gives you a very declarative way to manage your data, and encourages using your DB as your "single source of truth".

Querying everything through one API (which relays requests to other microservices, if necessary) and having one Postgres DB which acts as the "endpoint" for all of our data is a very clean model.

For edge cases, it's also possible to write custom resolvers. Prisma doesn't prohibit that.

Philosophically, is it really a "microservice" if it doesn't have its own database? In my opinion, if multiple services are ultimately all connecting to and storing their data in the same database, then you haven't really gained very much, since one misbehaving client can still take down everyone else's service. The point of microservices was always sold to me as "every team owns their own stack", and specifically if one team's stack goes down, everyone else can cheerfully continue. (Or less cheerfully, if the team whose stack went down was identity or user service.)