10. A database system configured to produce output data in response to instructions from distributed user terminals, said system comprising: a plurality of independent databases having a plurality of database schemas; means for establishing a communication channel with a user terminal; means for supplying data to said connected user terminal to identify available relational data queries corresponding to pre-determined data mappings between said independent databases; means for receiving data identifying a selected relational data query from said available selection; and means for implementing said selected query to produce output data from the database system.
10. A database system configured to produce output data in response to instructions from distributed user terminals, said system comprising: a plurality of independent databases having a plurality of database schemas; means for establishing a communication channel with a user terminal; means for supplying data to said connected user terminal to identify available relational data queries corresponding to pre-determined data mappings between said independent databases; means for receiving data identifying a selected relational data query from said available selection; and means for implementing said selected query to produce output data from the database system. 11. A database system as in claim 10, wherein said means for implementing said selected query is configured to supply Standard Query Language (SQL) instructions to the database system.