Re: Database design

Gene Wirchenko <genew_at_ucantrade.com.NOTHERE> wrote:

>On Wed, 22 Feb 2006 11:41:05 -0800, Mark Johnson
><102334.12_at_compuserve.com> wrote:
>>"Marshall Spight" <marshall.spight_at_gmail.com> wrote:
>>>Mark Johnson wrote:
>>>> "Marshall Spight" <marshall.spight_at_gmail.com> wrote:

>>Let's say you have a roster of US Presidents. Surely this is stored in
>>some database, somewhere.

>>It is entered row by row, tuple by tuple if you will. And their
>>position is entered, as well. While I can understand that one might
>>say the ranking would not necessarily apply, it also might. There is
>>an intrinsic order to the roster, after all. But by definition, that

> *An* intrinsic order?

> Is that intrinsic order by birthdate?

Please. Their position on the roster. JFK, it must be pointed out, was not President before the reign of FDR. FDR preceded him, instead.

> Is that intrinsic order the order in which they served? (If so,
>what about Grover Cleveland?)

Why parenthetical? And why would he not be listed? Is it that you don't know if the RM, or whatever you have in mind, could handle the scalars - 22, and 24? Could be a roster of local mayors, councilmen, what have you.

>>relation can NEVER be sorted?

> The *data* in the relation can be sorted.

Now wait a minute. Obviously - yes. But this theory is supposed to hold that a relation cannot be sorted, and cannot store the data in proper order.

If the 'data' in a relation is sorted, if each tuple occupies a list position with regard to other tuples, then you must admit that the relation is ordered. Maybe you want to say it's not set. Maybe it never was?

>>So a set cannot be ordered because to place it in any order is to
>>redefine it as non-set? So a roster can never be a set and a roster.
>>To become a set, the most important attribute of that set must be
>>discarded?

> What attribute is that?

His position in the lineup. And any changes during the game must also be approved. That attribute. The sort. The proper order.

> Why do you consider the order to be the most important attribute?

Game's got rules.

See, what you're trying to do is transform an intrinsic ordering to an equality of types, essentially. But the proper order is a unique sort of type. It's not like the others. And if you can sort the records in a file, the specific entities in an entity, the tuples in a relation, or whatever, then you have a set which is ordered. And if you declare that there can never exist a set which is ordered, if that's indeed what you do, then by definition you are not saying that the set is unordered, but rather are claiming that the order makes it something other than a set.

>>>> If a building is on fire, I for one would not stand there and say -
>>>> fire, what fire? Building, what building?

>>>After the building burned to the ground

>>But because someone kept saying, and confusing 'first responders' -
>>fire, what fire? Building, what building?

>>They had to get that information elsewhere.
Received on Thu Feb 23 2006 - 04:40:10 CET