Re: Real world issue:- OT recreational interval

Bob Badour ha scritto:

 Count is not idempotent, but in this case it does not operate
> on any duplication. (Replication means something different in the
> database field.)
>

 I also agree (can't believe I agree with Bob :) that for terminology it's better to avoid
 "replication" word in favor of "duplication" (if you see a better term please **notice**)

 If idempotent is not the term. What is a good term?

quoted from:
http://groups.google.it/group/sci.math/browse_frm/thread/17781c0124345f6e?scoring=d&hl=it

William Hughes

>More important perhaps, CountDistinct(2,2) = 1

>It is clear that "replication insensitive" cannot be the same as
>idempotent.
>For one thing, any constant function that can be replication
>insensitive
>(the definition given is not complete) is. No idempotent function can
>be constant.

http://groups.google.it/group/comp.databases.theory/browse_frm/thread/538735631f141027?hl=it

Marshall

>cd(cd(5,6),2)

...
>Consider how you would use + to make sum:
>(5+6)+2
>or binary min to make aggregate min:
>min(min(5,6),2)

>Extra credit:
>avg() is one aggregate that doesn't seem to fit with
>the rest. Why is that?

 3 questions:

 Now let's proceed further
 when you say:

1
 let me understand, are you implying that you could  compute the aggregate function recursively ?

2
 Would you please explain how do you compute the  following "aggregate" functions for n= 3:

• range of values (difference between max and min)
• median
• standard deviation

3.
 would you please provide the "binary" (n=2)  version of the above listed functions  

-P Received on Tue Sep 19 2006 - 09:17:16 CEST