Re: Database design
From: Alexandr Savinov <spam_at_conceptoriented.com>
Date: Mon, 20 Feb 2006 17:19:32 +0100
Message-ID: <43f9ec1d$1_at_news.fhg.de>
>> Roy Hann schrieb:
>> There is two separate issues:
>> - multidimensionality, and
>> - hierarchy
>> "Flat" in this context means (as far as I understand) the absence of
>> hierarchy, i.e., all the elements are at the same level.
>> Here it is also
>> assumed that the model itself is unaware if there is a hierarchy in the
>> data it models or not because it does not care - it is based on other
>> principles. However, the designer may well use it to model a
>> hierarchical data (as well as many other types of data organization). In
>> this case he/she must be responsible for the hierarchy maintenance
>> (integrity etc.) For example, we might model a tree but the model does
>> not know that it is a tree and hence cannot help us in its use.
>
> I agree. But so what? I could have an attribute of type "tree".
Date: Mon, 20 Feb 2006 17:19:32 +0100
Message-ID: <43f9ec1d$1_at_news.fhg.de>
Roy Hann schrieb:
> "Alexandr Savinov" <spam_at_conceptoriented.com> wrote in message > news:43f9d97f$1_at_news.fhg.de...
>> Roy Hann schrieb:
>>> "Mark Johnson" <102334.12_at_compuserve.com> wrote in message >>> news:acrfv1l86m3aqgfc2a3gj1btrbm1ja8r6p_at_4ax.com... >>>> "friend.05" <hirenshah.05_at_gmail.com> wrote: >>>> >>>>> I want to desgin a database for Tag Structure. Database design that > can >>>>> store heirarchy of tags developed my users. Present most popular > tags. >>>> You are asking if a relational database, with its flat >>>> tables/relations and link keys can be used to store nested markup - >>>> such as XHTML. >>> I struggle to see how something that is n-dimensional could be called >>> "flat". Roy
>> There is two separate issues:
>> - multidimensionality, and
>> - hierarchy
>> "Flat" in this context means (as far as I understand) the absence of
>> hierarchy, i.e., all the elements are at the same level.
> > I think you are reading something that was never written. The phrase that > was written was "a relational database, with its flat tables".
>> Naturally this
>> has nothing to do with n-dimensionality, i.e., n-dimensional model can
>> well be flat (non-hierarchical) and vice versa a hierarchical model
>> might well be one-dimensional. An example is any relational model which
>> is intrinsically non-hierarchical (that is, flat).
> > No doubt. I guess. >
>> Here it is also
>> assumed that the model itself is unaware if there is a hierarchy in the
>> data it models or not because it does not care - it is based on other
>> principles. However, the designer may well use it to model a
>> hierarchical data (as well as many other types of data organization). In
>> this case he/she must be responsible for the hierarchy maintenance
>> (integrity etc.) For example, we might model a tree but the model does
>> not know that it is a tree and hence cannot help us in its use.
>
> I agree. But so what? I could have an attribute of type "tree".
-- http://conceptoriented.comReceived on Mon Feb 20 2006 - 17:19:32 CET