We actually don't want apps to bundle MySQL -- we'd prefer they use sqlite. :) But the point is, it's up to the app. The app gets a slice of filesystem and they can use whatever infrastructure they want to store stuff to it.
We want the experience for users to be install app, use app, without worrying about setting up databases and such. We also want to enforce isolation between apps so one app cannot access another's data, and that's a lot easier to do if they aren't sharing a database. Considering these desires, it makes sense to say that apps should simply bundle their database of choice.
We want the experience for users to be install app, use app, without worrying about setting up databases and such. We also want to enforce isolation between apps so one app cannot access another's data, and that's a lot easier to do if they aren't sharing a database. Considering these desires, it makes sense to say that apps should simply bundle their database of choice.