Re: WWW/Internet 2009: 2nd CFP until 21 September

From: Walter Mitty <>
Date: Mon, 10 Aug 2009 19:10:47 GMT
Message-ID: <Xg_fm.1434$>

"paul c" <> wrote in message news:EJZfm.38509$Db2.34428_at_edtnps83...

> Walter Mitty wrote:

>> "paul c" <> wrote in message
>> news:fFXfm.38494$Db2.31022_at_edtnps83...
>>> Walter Mitty wrote:
>>>> ...
>>>> Anyway, I'm interested in whether XML falls under the topic of machine 
>>>> representation of the data and is therefore neither compatible nor 
>>>> incompatible with a relational view of data.
>>>> Or whether XML is an alternative tro the relational view of data, and 
>>>> therefore one that should be compared with the relational view of data 
>>>> with regard to benefits and drawbacks.
>>>> ...
>>> Here's an excerpt from an article two of the xml originators wrote 
>>> (
>>> "The nesting rule automatically forces a certain simplicity on every XML 
>>> document, which takes on the structure known in computer science as a 
>>> tree. As with a genealogical tree, each graphic and bit of text in the 
>>> document represents a parent, child or sibling of some other element; 
>>> relationships are unambiguous. Trees cannot represent every kind of 
>>> information, but they can represent most kinds that we need computers to 
>>> understand. Trees, moreover, are extraordinarily convenient for 
>>> programmers. If your bank statement is in the form of a tree, it is a 
>>> simple matter to write a bit of software that will reorder the 
>>> transactions or display just the cleared checks."
>>> Note the third sentence!   Basically, they admit that trees are not 
>>> universally useful.

>> The phrase I'm going to quote is this: "to make information
>> self-describing". This very same phrase was at the heart of the
>> motivation for databases back when I got my introduction to them in 1984.
>> There was a progression of how data definitions were managed that made
>> sense back then, as an explanation of how we got to the threshold of
>> databases.

>> It went something like this: In FORTRAN, data definitions were scattered
>> all over the program, in FORMAT statements. In COBOL, the definitions
>> were at least gathered at the front of the program, in the data division.
>> Soon afterwards record definition libraries began to be accepted in the
>> COBOL world. (BTW, I was never a COBOL guy). This enabled lots of
>> programs to share record definitions. Finally, databases that contained
>> their own schema, allowed data to be self describing.

>> I'm wondering if the people who invented XML didn't know that this work
>> had been done before, or if they regarded the work on databases as
>> worthy of being ignored.
>> In any event, they seem to have reinvented the hierarchical model of
>> data. This keeps happening. Next thing you know, we'll have somebody in
>> this forum telling us that Nelson Pick got it everything right. We've
>> already been down that road, but it can happen again.
> It takes guts to go after the big problems.   Going after small ones has 
> fewer risks, one of them is that the result will be labelled as the 
> product of small minds.  But it really is irresponsible to sell  the small 
> solution as if it solves a big problem.  At most, XML is a programming 
> technique that needs to be buttressed with a great deal of adhoc 
> infrastructure, like OO, not a semantic innovation, let alone some kind of 
> fundamental discovery..

I have scanned the first few paragraphs of the article you cited. I admit that I haven't read it all, or any of it carefully.

from the little I did read it seems clear to me that the originators of XML THINK that they have come up with a view of data that covers all of the same ground the the relational view of data covers. Or it's just possible that they never heard of the relational view of data. But just because they think that doesn't mean that you and I should think that.

So I return to my original question. Is XML simply a machine representation of data, or is it an alternative to the relational view of data? Another related question is, can you represent relational data in an XML document? Is anything gained or lost by doing so? Received on Mon Aug 10 2009 - 21:10:47 CEST

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