Re: Key attributes with list values was Re: What are the differences ...KEY

dawn wrote:
>
> Correct (if I understand). What does it mean that a list is a key? If
> I change one value in the list, does that make it a new key? I would
> think so.

If we substitute "int" for "list", what does the above look like?

"What does it mean that an int is a key? If I change one bit in the int, does
that make it a new key? I would think so."

I agree with both the list and the int version of the sentence. After all,
why should the particular type of the key change the way key values behave?

> It might [make sense to] model a proposition something like
>
> The team with people whose ID's are 112233 and 123456 has a best run of
> 38 seconds in the potato sack race.

Sure, that seems like a fine proposition to me.

> Most data modelers would choose to provide a team identifier rather
> than implement a multivalued ID (even MV developers).

As would I.

But again, in my view it's not generally a language designer's job to try
to dictate best practice. I instead like the idea of orthogonal features,
and recursive definitions. I like to make as many things as possible have
first class status in the language. (Although I draw the line at first class
variables a la SML, since that introduces identity.) If I decide that lists
shouldn't be keys, I'm going to have to put special purpose code in just
to check for that, or else build a more complicated, more rigid model that simply can't express the idea. Neither appeals to me.

Marshall Received on Sun Feb 26 2006 - 05:57:59 CET