Re: Value (was: Mixing OO and DB)

On 28 feb, 17:47, "Yagotta B. Kidding" <y..._at_mymail.com> wrote:
> Jan Hidders <hidd..._at_gmail.com> wrote innews:2d8e2a19-1dd3-49ed-89d3-5c2d9320d26a@e23g2000prf.googlegroups.com:
>
>  But what is essential for value types in the context of database
>
> > theory is that the elements of the sets have representations
> > associated with them, i.e., ways in which they can be represented in a
> > computer or to a human being. That IMNSHO is the defining
> > characteristic of a value data type vs. other data types, and thereby
> > also defines what is and is not a value.
>
> What are other abstract data types that are not values in the context of
> database theory?

Those that don't include such representations, of course. :-)

> To fast-forward through silly haggling over words, what is ADT according
> to you ?

For the purpose of this discussion: a structure that consists of a set and operations over that set, and where the set is left abstract, i.e., it is defined by giving the properties of the operations and not the internal structure of the elements in the set. Note that I'm cutting a few corners here, such as that we might be talking about multi-sorted algebras, but probably this will do for the time being.

• Jan Hidders