I found this thread about whether to update fact tables in data
warehouses, other than for errors in the data.

http://groups.google.com/group/microsoft.public.sqlserver.datawarehouse/browse_t
hread/thread/8ee96870badac8be/c1fcb42e0ce71039?lnk=gst&q=update+Fact+table+#c1fc
b42e0ce71039

The thread was from 2003, so I thought I would start this one.

It seems to me that the reason you wouldn't update data in a data
warehouse is that each row represents an event, and if the data has to
be updated later on to reflect something that was unknown when the
record was created, it was probably because a new event has occured to
create the piece of data.

Any thoughts?