I have several (Derby) databases with the same structure (populated by different machines), and want to combine them into one large database (using Java programming). The tables like tClient, tTransaction, etc. in each database have records that the other databases don't contain.
What are some fast ways of combining the databases into one large database "in a bulk fashion"?
Once I have a large database B and a little database L comes along later, I would like to write all of L's data into B.
I am comparing this "several-databases separately" with using a client-server version of Derby (several databases, each machine can work independently using its own fast resources; client-server, each machine writes to a centralized derby database)
Any and all tips and tricks would be appreciated, I will split the points between all the useful answers.