Pretty hard things

Hi I wonder how you suggest this to be solved: client | | | A / \\ / \\ / \\ / \\ B C With a client (for example a Java applet) I connect to A. At A I have some kind of a program, for example a Java program (CGI).I send SQL-queries to A. In A I have some kind of structure that keeps up with where the different tables and so on are (here B or C). Since I want to be able to do different checks at B and C (and A) before I get into the actual DB, I need some way to do the different operations on the data when it comes back to A. (For example I will check out what consultants that have been working at the both the companies having database B and C. I therefore retrieves the SSNs of all consultants at B and C. Then I want to make an "AND"-kind of operation at A ). Any good ideas? Please mail me at: d92-tsv@nada.kth.se Sincerely Tobias Svennebring