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kotlinlang

Is it ok having multiple room databases in an Android App. Like 10 or so?
Or is better to have only 1 with a lot of tables?
There are not many join queries in the existing codebase, in case this info helps.

One room db usually takes 3mb of memory if I am not wrong... But I would worry more about the modelling of your data and the ownership of it.
You don't need to decide to have one or 10... Depending on your business logic you could try to segment your data/models in a way that you may end up needing 3 dbs... All depends.

In my project we have one db to store translations, other to store FeatureA data... Those things don't need to talk with each other and different teams manage the data... So it made sense for us to have 2 dbs...