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Home -> Community -> Usenet -> comp.databases.theory -> Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]

Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]

From: Dan <dan_at_nospam.com>
Date: Fri, 24 Jun 2005 09:51:16 -0500
Message-ID: <F5Vue.32$_r5.4924@news.uswest.net>


On 6/24/2005 9:43 AM, Jon Heggland wrote:
> In article <V4Eue.128061$PH4.7042098_at_phobos.telenet-ops.be>,
> jan.hidders_at_REMOVETHIS.pandora.be says...
>

>>>Would that it were that simple. The same could be said about the "XML 
>>>data model", yet well-known researchers are happily reinventing the 
>>>square wheels of IMS and similar systems, apparently blissfully unaware 
>>>of the history and fate of hierarchical databases. I recently reviewed a 
>>>paper for VLDB which was quite scary in that regard---especially since 
>>>another reviewer, a really *big* name, said it was the strongest he had 
>>>reviewed.
>>
>>That's quite possible, but since I don't know the details I couldn't 
>>possibly comment.

>
>
> Yeah, I know it's anecdotal.
>
>
>>On the other hand, I know from personal experience 
>>that even some of the big names that are right at the core of the hype, 
>>are very clear about what they think XML is useful for what it is not 
>>useful for, and who would judge any claims that it would somehow replace 
>>the relational model as, and I quote, ridiculous.

>
>
> Which big names are those?
>
>
>>In that respect I really like the work by Torsten Grust et al that shows 
>>that you can do XML on top of an RDBMS, and that even though you are 
>>pushing the square XML peg in the round RM hole, you will still get 
>>something that works in many respects better than XML-native solutions.

>
>
> I've often wondered what exactly *is* an XML-native solution. Is it
> storing everything as text files?
>
>
>>So even if you are basically horribly abusing the RDBMS and shoving all 
>>that vile XML stuff down her throat, which it was not really built for 
>>in the first place, she will still happily and with a smile on her face 
>>provide you the scalability that we have become so accustomed to. Almost 
>>brings tears to my eyes. *snif* :-)

>
>
> Well, if you just treat XML document as a data type, there is no abuse
> involved. The RM *is* designed for this.
>
>
>>>The 
>>>question is whether such models are different *enough* from the network 
>>>model(s) to make it worthwhile to distinguish between them. The concept 
>>>exists, but that in itself does not mean very much.
>>
>>I don't completely agree that this is the right question. What has 
>>changed is not so much the data model, but the whole cloud of knowledge 
>>and silent assumptions that surrounds it. For the network model it was 
>>usually assumed that you wouldn't need query optimization. That 
>>data-independence was not possible or just a nice-to-have. In the 
>>beginning some also thought that about OODBs. That, in my experience, 
>>has changed.

>
>
> So it is a renaissance of the network model?
>
>
>>>(Another point is the question of what "OO" in that context really 
>>>means---the paper does not mention encapsulation, polymorphism or 
>>>inheritance. What is an object?)
>>
>>Well, the main reason for that is that these aspects are not relevant 
>>and somewhat orthogonal to the problem that it studies. I think I have a 
>>pretty good idea of their view on that, though.

>
>
> Ok ... but I though half the point of OODBs was to lessen the "impedance
> mismatch" between procedural OO programming languages and declarative
> databases (by making the databases less declarative). What is the
> motivation now?

Procedural OO programming? Isn't that an oxymoron? Received on Fri Jun 24 2005 - 09:51:16 CDT

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