Replication allows you to copy data on a regular basis to multiple remote databases. If you need to have updates to a master database automatically copied to other databases, you can use the replication features of DB2 to specify what data should be copied, which database tables the data should be copied to, and how often the updates should be copied. The replication features in DB2 are part of a larger IBM solution for replicating data in small and large enterprises.
The IBM Replication tools are a set of DB2 DataPropagator programs and DB2 Universal Database tools that copy data between distributed relational database management systems:
Data can also be replicated to non-IBM relational database management systems by way of DB2 DataJoiner.
You can use the IBM Replication tools to define, synchronize, automate, and manage copy operations from a single control point for data across your enterprise. The replication tools in DB2 Universal Database offer replication between relational databases. They also work in conjunction with IMS DataPropagator (formerly DPropNR) to replicate IMS and VSAM data, and with Lotus NotesPump to replicate to and from Lotus Notes databases.
Replication allows you to give end users and applications access to production data without putting extra load on the production database. You can copy the data to a database that is local to a user or an application, rather than have them access the data remotely. A typical replication scenario involves a source table with copies in one or more remote databases; for example, a central bank and its local branches. At predetermined times, automatic updates of the DB2 databases takes place, and all changes to the source database are copied to the target database tables.
The replication tools allow you to customize the copy table structure. You can use SQL when copying to the target database to enhance the data being copied. You can produce read-only copies that duplicate the source table, capture data at a specified point in time, provide a history of changes, or stage data to be copied to additional target tables. Moreover, you can create read-write copies that can be updated by end users or applications, and then have the changes replicated back to the master table. You can replicate views of source tables, or views of copies. Event-driven replication is also possible.
You can replicate data between DB2 databases on the following platforms: AIX, AS/400, HP-UX, Linux, Microsoft Windows 95, 98, 2000, and NT, OS/2, OS/390, SCO UnixWare, Sun Solaris, Sequent, VM, and VSE. You can also replicate data between DB2 and the following non-DB2 databases (with DB2 DataJoiner): Informix, Microsoft Jet, Microsoft SQL Server, Oracle, Sybase, and Sybase SQLAnywhere. In conjunction with other IBM products, you can replicate DB2 data to and from IMS, VSAM, or Lotus Notes. Finally, you can also replicate data to DB2 Everywhere on Windows CE, or Palm OS devices.
There are two components of the IBM Replication tools solution: the Capture program and the Apply program. You can set up these components using the DB2 Control Center. The operation and monitoring of these components happens outside of the Control Center.
The Capture program captures changes to the source tables. A source table can be:
The changes are copied into a change data table, where they are stored until the target system is ready to copy them. The Apply program then takes the changes from the change data table, and copies them to the target tables.
Use the Control Center to:
For more information, see the Replication Guide and Reference.