Question

My program download a.sqlite3 file in server

and b.sqlite3 file is already in local ios.

I want to join table in downloaded a.sqlite3 with in b.sqlite3

so I am thinking of copying from table in a.sqlite3 to b.sqlite3
and joining the tables in the same database/

or

just joining a.sqlite3's table with b.sqlite3's table.

What is the recommended way or is there any alternative?

Answer 1

It is a best practice is to use the same database with multiple schemas. Each schema can be put on its own file, which can then be backed up easily if that is the reason for separation of the data across dB in the first place. A

Also you cannot have foreign key constraints across multiple databases and which is a major drawback

You may want to read up on this post http://www.unityjdbc.com/doc/multiple/multiplequery.html