Distributed unit of work allows an application to access more than one database within a unit of work; that is, the application can switch between databases before committing the data. This gives an application programmer the ability to do work involving multiple databases, local and remote, at the same time.
DB2 Connect always lets you read multiple databases within a unit of work. Whether you can update multiple databases depends on the products you are using:
In the TP monitor environment CICS for AIX or the Encina Monitor acts as the XA transaction manager, coordinating two-phase commits, rollbacks, and recoveries. The combination of DB2 Connect and the DRDA server can be considered an XA resource manager.
| Note: | TP Monitor support for two-phase commit via DB2 Connect Version 5.0 is only supported over SNA connections. There is no equivalent support for TCP/IP connections, so that - in XA environments - when DRDA servers are accessed using TCP/IP, read-only connections are all that is provided. |
In order to take advantage of distributed unit of work support, you must be familiar with the concepts described in the Administration Guide and the SQL statements described in the SQL Reference.
For more information about two-phase commit, see: Setting up Two-phase Commit Using SNA in DB2 Connect Enterprise Edition Quick Beginnings, and Setting up Two-phase Commit Using TCP/IP in both DB2 Connect Personal Edition Quick Beginnings and DB2 Connect Enterprise Edition Quick Beginnings.
For more information about transaction monitors, and setting up a TP monitor environment, see the CICS for AIX Customization and Operation Guide, and Setting up DB2 Connect with TP Monitors in DB2 Connect Enterprise Edition Quick Beginnings.