Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> comp.databases.theory -> Re: Use of the term "hierarchy"

Re: Use of the term "hierarchy"

From: Alexandr Savinov <spam_at_conceptoriented.com>
Date: Sat, 27 Aug 2005 15:42:52 +0000
Message-ID: <431089f8@news.fhg.de>


Kenneth Downs schrieb:
> Consider the canonical example of employees and their supervisors. This is
> usually presented as a hierarchy of like items. It seems however that we
> do this only because it is far too much bother to store and keep up-to-date
> the actual structure of a corporation in tables. But in fact, if it were
> possible to change tables as often as corps change org structures, we would
> most accurately keep records by having a table of vp's, a table of
> directors, table of managers, and so forth.

There exist the following problems for that:

One serious problem is that we do not have an appropriate query language and other data manipulation facilities for dealing with many tables. SQL is aimed at manipulating records, not tables.

The second problem is that having many tables means that records cannot migrate between them (easily). Changing a group/set/category means changing a table but it is impossible because it is physical container (rather than logical in the case where group/set is represented by a referenced record).

The third problem is that there is only one parent table for each record while for logical parents (represented by field values) there may be more than one group/category.

--
http://conceptoriented.com
Received on Sat Aug 27 2005 - 10:42:52 CDT

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US