Distributed relational databases
The database managers in a distributed relational database communicate and cooperate with each other in a way that allows a Db2 application program to use SQL to access data at any of the interconnected computer systems.
A distributed relational database consists of a set of tables and other objects that are spread across different, but interconnected, computer systems. Each computer system has a relational database manager, such as Db2, that manages the tables in its environment. The database managers communicate and cooperate with each other in a way that allows a Db2 application program to use SQL to access data at any of the computer systems. The Db2 subsystem where the application plan is bound is known as the local Db2 subsystem. Any database server other than the local Db2 subsystem is considered a remote database server, and access to its data is a distributed operation.
Distributed relational databases are built on formal requester-server protocols and functions. An application requester component supports the application end of a connection. It transforms an application's database request into communication protocols that are suitable for use in the distributed database network. These requests are received and processed by an application server component at the database server end of the connection. Working together, the application requester and application server handle the communication and location considerations so that the application is isolated from these considerations and can operate as if it were accessing a local database.
For more information on Distributed Relational Database Architecture™ (DRDA) communication protocols, see DRDA Volume 1: Distributed Relational Database Architecture (Open Group Library - Data Management Standards).