As I said in my comments, I would use a single database with all the data(from all the possible users) in each tables you have, with another extra column representing the actual user identifier(present in whatever table you need user identification). You'll then use this column to filter the normal database queries(insert, query etc) to get/modify only the data for that particular user. That identifier would have to be passed through the Uri
if you use a ContentProvider
, and then appended to the normal selection clause with AND user_identif=user_id_extracted_from_uri
.
And you could use the email address as the identifier, which would be more reliable across devices instead of some generated user ids.