Re: Multiplicity, Change and MV


x wrote:
"dawn" <dawnwolthuis@xxxxxxxxx> wrote in message
news:1145292548.823950.44180@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

x wrote:


It just struck me that you are bi-lingual with English as a 2nd (or
nth) language while I don't speak the RM as handily as MV, for example.
A minor challenge for both of us.

I don't know "English" - the query language of some Pick system.

Yes, that is the Reality flavor of Pick, so many people still call the
Pick query language English. Others call it Access, even though they
clearly didn't end up on the winning side of that lawsuit. The fact
that it has no name (many, many names) is one of the problems in even
writing about it. The only name in common for all is the original spec
name of GIRLS, which was a reuse, it seems of this acronym, so using
that is not without problems either.

I wonder if those who use them are confused by them or there are some
precise definitions of them.

There are some terms with very precise definitions such as file,
attribute/field, value (on my site in the MultiValue triology,
particularly the Data "flashcards"), but since the model is not aligned
precisely with any single, simple, mathematical model, there is a lot
that is not nearly as precise as a mathematical definition would be.

Pity.

The terms are just as precise as the words in the data in the database,
however. As long as language is common to both, language is what is
used to understand the system and to discuss any issues. Pick is based
on the language of asking questions and getting responses, where XML is
based on the language of documents. That is why there is more
commonality between Pick and XML than between either of these and the
mathematically-based (rather than language-based) SQL-DBMS systems.

It just occured to me that other possible problem with MV systems beside
loops might be the [im]possibility to represent relations over the same
domain like r(A,A,A,A) where A is an element/entity/whatever like Courses,
Lecturers etc.
Could you provide an example for this ?

The domain for every (non-binary) attribute in Pick is String.
Everything else, such as indicating that the string is a Date, is a
description of the data. A single value can be described as a Date and
as a String, for example. There is no problem having a relation with
multiple courses. Each course would be named differently and would be
a String.

I don't know if that answered the question. Let me know if I missed
the mark. Cheers! --dawn

.

Relevant Pages

  • Re: Operator overloading in C
    ... All development of C as an independent language has ... making any changes or improvements to the standard ... The lack of a counted string data structure, ... Pointers can't be used for arg1 or arg2. ...
    (comp.std.c)
  • Re: syntax...
    ... B&D on the part of the language designer. ... probably handle concatenation of string literals by itself, ... bitwise XOR, or if not that, then exponentiation.) ...
    (comp.lang.misc)
  • Re: My investigations into Godels Incompleteness Theorem
    ... string. ... sentences (even sentences not in the same language) have in common. ... The denotation of a sentence is the truth value (either truth or ...
    (sci.logic)
  • Why C Is Not My Favourite Programming Language
    ... C has no string type. ... compiler take care of the rest. ... Why does any normal language ... the programmer fail. ...
    (comp.lang.c)
  • Re: Controlling Javascript from server side
    ... but five different language implementations here. ... 'true' means that the request must be handled asynchronously. ... There is exactly *no* reason for such a thing here. ... | percent-endoded string). ...
    (comp.lang.javascript)