Re: Conceptual model based on set theory
Date: Fri, 11 Sep 2015 11:35:51 -0700 (PDT)
Message-ID: <0a9c133e-884d-4981-a098-7b75fcff1d4b_at_googlegroups.com>
> In a similar way we can obtain conceptual model for states of entities and
> for states of relationships. I mean the conceptual model based on set
> theory.
Now I will explain how we should work with the states. In my paper "Some ideas about a New Data Model", posted in 2005 on my web site http://www.dbdesign10.com and which was presented on this user group in 2005, I wrote in section 2.3 the following:
As stated in 1.1 one entity (similarly with a relationship) takes the form
(P, E, A1,...,An)
Where P is the identifier of the state of the entity ( relationship )
E is the identifier of the entity
A1,...An are attributes of an entity ( relationship)
Each attribute, including E and P, can have different sets of knowledge F
associated to them.
Thus:
P has knowledge Fp1, Fp2,...,Fpi E has knowledge Fe1, Fe2,...,Fej A1 has knowledge F11, F12,...,F1k ... (3) .
.
.
An has knowledge Fn1,Fn2,...,Fns.
Considering the above, I will now write a conceptual model based on sets, for the states of entities (relationships): {P, E, A1, ... , An} = {P, E} U {P, A1} U ... U {P, An}
Now we can join some knowledge with any of these binary sets. For example, we can join this knowledge about attribute A1 to binary set {P, A1} and we will get this knowledge about attribute A1. This knowledge contains facts about attribute A1: {P, A1, F11, F12, ... , F1k}
So knowledge about the attribute A1 was presented with the appropriate set of facts about attribute A1. If we take the second line from example 2.5, from the aforementioned paper, then we have the following set:
{ 117, $2000, 5/Oct/04, 28/Oct/04, Mick Smith, 6/Oct/04, 29/Oct/04, Lee Evans},
Where 117 is the identifier of the state of the entity and $2000 is one attribute from the entity.
Vladimir Odrljin Received on Fri Sep 11 2015 - 20:35:51 CEST