Re: Transitive Closure with XDb1

> > In addition, using the more appropriate schema T_Contains, T_Planet
> > and T_Person, how does one use TClose()? XDb1's T_Relative() works for
> > hierarchies consisting of different kinds of things...

> Paul wrote: I'm not sure what you mean by this schema 
>             - could you expand on it?

I assume universe, planets and persons are different types thus require different tables to "classify" them and minimize NULLs since each type will have different attributes. Thus an "ideal" RDM representation might be:

T_Universe
GUID Name Age ...
---- -------- --------
1 Universe Infinite

T_Planet
GUID Name Mass ...
---- ----- ------
2 Mars 100 GKg
3 Venus 10 GKg

T_Person
GUID Name Favorite Color ...
---- ------ --------------
4 John Red
5 Mary Blue

T_Contains
Whole Part

---------- -------


->Universe ->Mars  (->XYZ represents appropriate GUID)

->Universe ->Venus


->Mars     ->John

The problem with the above is the impracticality (but not impossiblity) of resolving GUIDs in T_Contains. (I am sure there are other, less than ideal solutions)

> Paul wrote: By definition, transitive closure is only for hierarchies > of the same type of thing.

Since XDb1 uses a different data model and different set of definitions, it is not limited to same type of things in an hierarchy. Received on Fri May 14 2004 - 23:22:28 CEST