Re: RDBMS? -- another point

[Ted Nelson <ted@xxxxxxxxxx>]

Andrew points out:

>data elements are not required to partcipate in
>any particular dimensions. 

This can be misleading.  "Participation" in a dimension
 currently has the obscure meaning that a cell has *links*
 in a given dimension.  All cells *exist* in all dimensions.

Best, T


At 03:13 PM 11/2/98 +1100, you wrote:
>On Sat, Oct 24, 1998 at 07:20:32PM +0900, Kenichi Unnai wrote:
>> I recently knew about RDBMS (Relational DataBase Management System).
>> Do you know that?
>> If you do, do you find any difference between zigzag and RDBMS?
>> 
>> I know zigzag is not database, it's environment, but I think it's the same
>> thing with the concept of hypertext.
>> 
>> Hypertext is also the environment, but in another point of view,
>> it's world-wide distributed database system.
>> 
>> I need to explain to some guys how different zigzag and RDBMS.
>> I'm striving to do, but I can't have a clear idea.
>> 
>> Or can it be compatible with each other?
>> What I want to do is to get a clear explanation that how different, and
>> what the good/bad point are there.
>> 
>> Any idea?
>
>Well, the concept of "database" is very broad (it just means a collection
>of data which users can access and modify) and both Zigzag and hypertext
>build on top of collection of data.  However, a relational database
>(RDBMS) is a specific kind of database where the data is structured into
>"relations", defined as tables containing rows ("records") and columns
>("fields").
>
>Hypertext (or hypermedia) provides for connections between data in the
>form of "links" and/or "transclusions", which can be layered on top of
>just about any kind of database system including RDBMSes.  However the
>hypertext/hypermedia concept does not prescribe any particular structure,
>instead enabling each user to create their own structural arrangements
>of the underlying information.
>
>Zigzag is in a sense a specific example of hypermedia because it also
>provides for connections between data elements including both links
>and transclusions ("clones"), but it does enforce a few structural
>rules - all links must be typed (in a named dimension), bidirectional
>and one-to-one, and data elements are not required to partcipate in
>any particular dimensions.  These rules could also be implemented as
>an additional layer over an existing RDBMS - indeed this is one of the
>topics currently under discussion on the Zigzag developer mailing list.
>However a conventional RDBMS by itself does not provide the more powerful
>structuring and viewing facilities of Zigzag.
>
>Hope that helps,
>		*** Xanni ***
>-- 
>mailto:xanni@xxxxxxxxxx                         Andrew Pam
>http://www.xanadu.com.au/                       Technical VP, Xanadu
>http://www.glasswings.com.au/                   Technical Editor, Glass Wings
>http://www.sericyb.com.au/sc/                   Manager, Serious Cybernetics
>P.O. Box 26, East Melbourne VIC 8002 Australia  Phone +61 3 96511511
>
>
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Theodor Holm Nelson, Visiting Professor of Environmental Information
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