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Home -> Community -> Usenet -> comp.databases.theory -> Re: THe OverRelational Manifesto (ORM)
Hi,
> One month ago I sent very simple question to dbdebunk.com.
>
> "...initial assumption, which all reasonings and conclusions are built
> on, does not seem to me full. I mean the question " What concept in the
> relational world is the counterpart to the concept "object class" in
> the object world?" and two answers
> 1. domain = object class
> 2. relation = object class
> I'm not sure that these two answers (of course, the first one is true
> and second one is false) are only possible ones.
Indeed, but if the first one is the true then all the others are false.
3. scalar type = object class
is also true but it is the same as 1.
But of course there are more relationships between OO and the Relational Model.
For instance:
operator = method
pointer = OID
scalar value = object
scalar variable = object
scalar value = instance
Etc.
> And what is more - I'm
> not sure, that the question itself is only one question we should
> answer to find relationship between objects and relations. Really these
> assumptions look like just your personal opinion, because there is no
> any argument for adequacy of only these cases.
If classes and domains are the same then we have a relationship between objects and relations. Loosely, the objects are the scalar values holded in the relations.
> How can you argue this assumption?..."
It is evident for everyone who knows the meaning of "relationship".
reˇlaˇtionˇship n.
The condition or fact of being related; connection or association.
www.dictionary.com
classes/domains are a connection between objects and relations.
> Once again. TTM is buinl on very simple assumptions. They aren't wrong
> (I think so) but nobody proves that this is only possible question and
> these are only possible answer. For me it seems like fundamentally
> other approach can exist and it may be just interesting thing to
> understand if this approaches can really exist. I'm sure it exists.
Please, return when you have a true new approach. There is nothing new in your stuff.
> Of course you can shuffle words "stupid" "idiot" and "shit" (You seem
> to be master of this action) But on
In this case they seem to be justified words.
> http://www.theorm.narod.ru/david_portas_asks.htm (at the end of page)
> you can find simple question. Show me the answer in Tutorioal D.... or
> continue to shuffle words....:)
CREATE CLASS SHIPMENT
{
No INTEGER;
WareFrom WAREHOUSE;
Items SET OF //-- and this is a set of invoice lines
{
Article STRING;
Pieces INTEGER;
}
}
var Shipment base relation { No Integer, WareFrom Warehouse, Items relation { Article Char, Pieces Integer } } key { No };
But this is not a very good design (although a lot better than your's). It would be better to do this:
var Shippent base relation { No Integer, WareFrom Warehouse } key { No
};
var Items base relation { No Integer, Article Char, Pieces Integer }
key { No, Article };
constraint ItemsHaveShipment Is_Empty(Items not matching Shipments);
Regards
Alfredo
Received on Wed Apr 19 2006 - 04:37:42 CDT
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