Does anyone know if I can make arrays in the datamodel unique? In this example, I want every room to have a set of allowed domains (e.g. prisma.io and prisma.com) and these domains must not be used by other rooms

To do so you would have to define the relation from Domain -> Room as 1-n. So that the relation there is a Room, not a list of rooms.

good point, thanks 🙂