# Re: Idempotence and "Replication Insensitivity" are equivalent ?

Date: 23 Sep 2006 09:50:19 -0700

Message-ID: <1159030219.389668.309210_at_h48g2000cwc.googlegroups.com>

Chris Smith wrote:

*> <pamelafluente_at_libero.it> wrote:
*

> > For some reason some of you guys want to stick to a definition that is

*> > proving to be too strict, not even coerent since treat AVG and MEDIAN
**> > are treated differently (I have shown that conceptually they are both
**> > systesis of a distribution). Not practical.
**>
**> Pamela,
**>
**> Please reflect on what you're doing. You are coming into a newsgroup on
**> database theory (and then adding one on math; and yes, you added it);
**> and then telling us that you don't know anything about database theory;
**> and subsequently complaining that the standard formulation of aggregate
**> functions is wrong.
*

> It's not wrong. It is widely known and accepted

*> that the median calculation fits poorly, if at all, into the category of
**> aggregate functions.
*

Do you have a reference for the non-acceptance of the median function ? What about standard deviation ?

>You insist on acting like this result is an

*> invention of the people you are speakig to on this newsgroup; in fact,
**> it is probably older than I am.
**>
**> If you think that query languages should have a median function, and
**> that it should look just like an aggregate function, then fine. You can
**> choose a DBMS that does so, or even write a DBMS that does so if you are
**> so inclined. It remains true that your syntactic similarity has nothing
**> to do with aggregate functions, and that your implementation of the
**> function will look extremely different from a reasonable implementation
**> of any aggregate function.
*

What is a "reasonable implementation of any aggregate function" and assuming there is such, what has the implementation got to do with the abstract notion of aggregate function ? Received on Sat Sep 23 2006 - 18:50:19 CEST