Should XML ever be presented to 'users' (Was: Re: [xml-dev] ANN: a porta

["Pete Cordell" <petexmldev@codalogic.com>]

Roger and Steve's recent posts have made me think that we differ on how we 
see the role of XML.

By analogy to a cruise liner, I see XML as being part of the engine room of 
a ship, deep down in its bowels.  The regular (non-expert) users are in the 
extravagantly furnished ballrooms, completely oblivious to the XML 
shovelling that goes on below to keep the ship moving forward.  They don't 
know, or care, that XML is being used.

As such it should be only in exceptional circumstances that a non-expert 
user sees raw XML.  Consequently, anybody that does see the XML can be 
expected to have some degree of specialist, domain-specific knowledge. 
Therefore, expecting a person that interacts directly with the XML to be 
able to convert between different measurement systems (assuming that's the 
nature of their application domain) is quite reasonable.

What are others' opinions?

Thanks,

Pete Cordell
Codalogic Ltd
Twitter: http://twitter.com/petecordell

----- Original Message ----- 
From: "Stephen D Green" <stephengreenubl@gmail.com>
To: "XML Developers List" <xml-dev@lists.xml.org>
Sent: Saturday, April 09, 2011 6:06 PM
Subject: Fwd: [xml-dev] ANN: a portable data component -- length



Normal form isn't the only way to express data. It works for some
scenarios but decidely not for others; take analytical databases, data
marts, data warehouses, etc. For ages in the UK we had to have the
price of loose fruit and vegetables on our shop shelves expressed in
both price per imperial and price per metric weight. We still have
shoes and clothes sold in UK and EU sizes. We don't give people one
price and say "go work the other price out" or one size and say "go
work out the other size; here is the conversion factor"... So we often
produce price lists, I expect in XML, with multiple prices in mutliple
currencies and we design database table deliberately with redundant
information so that there is no need for extra time spent
dereferencing information held in separate tables. I think Roger's
examples hold well.

On 09/04/2011, Liam R E Quin <liam@w3.org> wrote:
> On Sat, 2011-04-09 at 11:10 -0400, Costello, Roger L. wrote:
>
>> Here is the altitude of an aircraft, expressed in both feet and meters:
>>
>> <altitude>
>> <feet>12000</feet>
>> <meters>3657.6</meters>
>> </altitude>
>>
>> It is important that the two length values are consistent:
>
> The right way to mark this up in most cases is to store only one value
> and convert as needed.
>
> See Normal Form in database theory: information should never be
> duplicated. That way it can't get out of sync.
>
> So my answer is simply, "don't do this."
>
> Instead, e.g.
> <measurement>
> <name>altitude</name>
> <value units="m">3657.6</value>
> </measurement>
>
> (I'd use metric/SI units in a program as they're easier to deal with,
> and mixed-based ambiguity like 3 feet 7 inches doesn't occur)
>
> Best,
>
> Liam
>
> --
> Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
> Pictures from old books: http://www.fromoldbooks.org/
> Occasional blog: http://www.barefootliam.org/
> The barefoot typographer
>
>
>
>
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--
----
Stephen D Green

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