The only DB2 edition missing this federation function today is DB2 Express-C (and I have no idea why it's been omitted). Of course, you may be wondering what 'homogeneous' federation has to do with Informix if we're talking about DB2 editions :) The answer can be found in DB2 9.1's announcement letter
. In it, IBM defined homogeneous federation as being federation of it's two relational database families at that time:
"IBM Homogeneous Federation Feature allows you to manage and access DB2 and Informix data stored on remote data servers as local tables within your DB2 server."
In the 9.5 time frame, an IBM annoucement letter
said that this function would be integrated into the DB2 editions available at that time. The relevant text from that announcement is:
To allow for easier data sharing between multiple IBM data servers the Homogeneous Federation feature is being included with all editions of DB2.
Notice it says "IBM data servers" and not "DB2 servers." The only catch is that it isn't installed by default. You must go through the DB2 install's custom install path to get it. For example, here's what I see in my 9.7's custom install path:
Great :) That only leaves one question...
What About Using This Federation with SQL Replication?
SQL Replication has been built into DB2 since Version 5 in 1997. Once data federation was added to DB2, the SQL Replication administration tools (currently the Replication Center and the asnclp script processor
) were updated to allow replication between DB2 and Informix. Just in case you're wondering, the DB2 license information documents do not restrict this function. For example, see the DB2 ESE 9.7 license information document
One note about this is that, if you want to capture changes from Informix databases, SQL Replication offers only trigger-based capture mechanisms. If you need to capture changes from Informix, a much better alternative is InfoSphere Change Data Capture
's (CDC's) log-based capture for Informix.