Execute a query to three DB in parallel

Question

Hi,
I would like to execute a query to three external servers in parallel in order to obtain the result of an SQL query.
The result I want to obtain is a list of objects which pertain to a user. This user may have objects in one, two, or three databases.
The way of doing it should not consume too much memory. I'm using Java mobile and have limitated memory.
Could you please tell me what's the better way of doing this? Can you provide an example?
Thanks in advance

Answer 1

I wouldn't create three queries from the device itself. Create a separate service that does the three queries for you (could be as simple as a java webserver with a servlet) and reference that service in your java mobile application. Far easier to make secure also.
And yeah to do three queries at once, you'd need multithreading I'd say. Or just execute the three consecutively, they shouldn't take much time anyway.