Re: 1GB Tables as Classes, or Tables as Types, and all that refuted

On Wed, 24 Nov 2004 21:07:08 +0100, "Ja Lar" <ingen_at_mail.her> wrote:

>
>"Alfredo Novoa" <alfredo_at_ncs.es> ...
>
>>>But the set of values that a relation is ("contains") cannot be mapped to
>>>the set of values that a type is ("contains")
>>
>> They can be mapped but then you are not mapping a relation to a type,
>> you are mapping the values contained in the tuples of a relation to
>> the values of a type. This is a value to value mapping.
>
>A "value to value mapping" in contrast to ...?

A bacon to velocity mapping.

>By what measure is that not a mapping from the relation (the set of values)
>to the type (the set of values) ?

By all measures. A relation is not a set of values it is a single value.

To map the values contained in the tuples of a relation to a type could be something like this:

type dumb possrep {integer} constraint dumb between 0 and 9;

relation {

  tuple { a 0, b 1, c 2, d 3, e 4 },
  tuple { a 5, b 6, c 7, d 8, e 9 },
  tuple { a 5, b 2, c 4, d 4, e 7 },
  tuple { a 1, b 2, c 0, d 1, e 9 }

There is a correspondence between the values contained in the tuples of the relation and the values specified by the type, but this is a completely stupid and useless mapping.

But again, there is not a mapping between the type and the relation.

Regards Received on Wed Nov 24 2004 - 22:34:05 CET