Oracle7 Server Distributed Systems Volume I: Distributed Data
Back-End Services
Besides acting as a database server, a server can provide other multi-user service applications for mail, document management, and so on.
SQL
The most basic tool for data access is the structured query language (SQL). Many SQL and SQL-generating tools have been developed for accessing remote data. Although the front-end application presents a much simplified method of creating queries for the user, the result of the query that is passed to the server is SQL.
Remote Procedure Calls
Similar to local procedure calls where frequently used code is stored as a procedure or routine, remote procedure calls (RPCs) allow the same functionality over a network of systems. When a program executes the stored code, it passes on any necessary parameters in the call.
Because the procedure is located remotely, however, it must be coded to understand what to do at the remote location, and how to return the results to the requesting application.