Re: How Postgresql Compares For Some Query Types

> 
>     I'm a little unclear on what a "fact table" is.  Can you explain?

Good question... The idea comes from data warehousing where a typical data 
construction involves two "types" of table :

dimensions : time, location, ethicity....( essentially denormalized lookups )
facts      : observations, accidents, sales ....

facts have a composite primary key , each componant of which is a foreign key 
for one of the dimensions.

If drawn with the fact table(s) in the center and dimensions around about, then 
the ERD looks like a "star". Hence the names "star schema" and "star query"

A quick search located a vaguely helpful page : ( apologies about the source )

http://www.oradoc.com/ora816/server.816/a76994/schemas.htm

A much better source is Kimball's book "The Data Warehousing Toolkit".

regards

Mark