Re: Aggregates: Largest Groups

Sampo Syreeni wrote:
...
> Exactly correct. He just tried to improve what he saw, and hit upon
> gold with RM. Then he and perhaps a whole generation of folks stopped
> there. I on the other hand think the evolution Codd (and many other,
> different kinds of advocates for high level primitives+structure)
> started should continue. In *theory* it could overtake procedural
> programming as a paradigm as well, but practically I don't think it
> ever will (there are a number of complexity proofs in the way). ...

As far as the original question is concerned, it's not just complexity that's in the way. At one point David F talks about the average speed of a group of vehicles then calculates a new group by taking the average of the averages of two groups. An average of averages is generally not equal to an overall average. So I'd say that one big impediment to progress is a general inability to state requirements.

Eg., is the average speed of a car moving over one klic at 200 kph and at 100 kph over a second klic 150 kph or 133.3 kph? David F seems to think it is 150 kph, I think this is usually called an unweighted average. So right off the bat, the distance is fixed but it isn't clear whether calculations should be based on recorded speeds or recorded elapsed times. In other words, from the requirement, we can't decide what to record. I would call this a non-starter, it's confusion, not complexity! The flurry of questions the OP generated reflects this. I suppose Date might say that the predicate is ambiguous. Received on Sat Apr 10 2010 - 17:58:32 CEST