Better support for Postgres Schemas

[jimsimon]

This is similar to #40 but would be tailored to Postgres specifically. The idea would be to leverage SET schema or SET search_path inside of a PrismaClient middleware. The tenant model would need a schema property, and ideally this would support creating/using a different user per schema for improved data isolation and security.

Right now we can use Postgres schemas via different connection urls, but I suspect that's also spinning up a separate connection pool per schema which can be mitigated by leveraging SET schema.

[jimsimon]

Nevermind, I don't believe this is possible with the current middleware support. I've opened prisma/prisma#3968. Hopefully they'll support it or provide an alternative workaround.

[Errorname]

Hi @jimsimon! This sounds indeed like a good idea, but I don't think it's possible with the current capabilities of Prisma at the moment. I'll close this issue for now, but don't hesitate to reopen, or create a new one, if it becomes possible in the future.