Elements vs. Attributes - was Re: [ubl-ndrsc] Minutes for 6 March 2002UBL NDR meeting

[Eduardo Gutentag <eduardo.gutentag@sun.com>]

There's one thing that has just occurred to me, related to the discussion we
had this morning.

While we were talking, the mental model I had was that of an amount X, expressed
as a currency Y; thus, I agreed to:
<amount currency="Y">X</amount>

This was clarified later as:
<amount currency="Y">
	<price>X</price>
</amount>

(for those who weren't in the discussion, please remember these are mental
models, or just examples, and do not intend to convey anything about element
tag names, etc.)

And looking now at it, I see that what was originally metainformation about
the value X has now migrated to be treated as metainformation of <amount>,
whereas it really should be metainformation of <price>; this may become
particularly important if <amount> were to become a more complex element
that contains more than price.

So, I'm not sure whether I'm nitpicking or not, I'd like to propose
that the actual example be
<amount>
	<price currency="y">X</price>
</amount>

Or am I totally wrong, and currency is actually metainfo on amount?

Matthew Gertner wrote:
> 
> The meeting was unchaired but we went forward anyway.
> 
> 1. Roll call
>     Bill Burcham                YES
>     Mavis Cournane      YES
>     Mark Crawford
>     Fabrice Desré
>     John Dumay
>     Matt Gertner                YES
>     Arofan Gregory      YES
>     Phil Griffin
>     Eduardo Gutentag    YES
>     Eve Maler
>     Dale McKay
>     Joe Moeller
>     Sue Probert
>     Ron Schuldt
>     Lisa Seaburg
>     Gunther Stuhec      YES
>     Paul Thorpe
> 
>     Quorum not reached as of x:15.  We proceeded informally.
> 
> 1'. Next week's call
>      No real chair. Needs to be discussed on the list.
> 
> 2. Acceptance of minutes of previous meetings
> 
>     Deferred.
> 
> 3. Adoption of agenda
> 
>     Short discussion of Bill's paper
>     Elements vs. attributes
> 
>     Adopted informally. Other items deferred.
> 
> 4. Action item review
> 
>     Deferred.
> 
> 5. Tag names
> 
> Short discussion of Bill's paper. Arguments made both for and against
> binding tag names in various ways to type names. Action to everyone to read
> latest version of Bill's paper (will be posted to list) as input for final
> decision.
> 
> 6. Elements vs. attributes
> 
> Gunther has a new position paper. He argues that attributes could be used
> more than previously discussed. An example in currency code: making it an
> attribute eliminates the need for additional child elements, is more
> readable and is more efficient. Also proposed for:
> 
> * ID/IDREF
> * xml:lang (Arofan points out that there are difficulties enumerating this
> in practical cases, Gunther says that another attribute could be used for
> this purpose)
> 
> Gunther says he still has to outline treatment of empty elements. Arofan
> says that a lot of elements will be empty in this case, since all data will
> be in attributes (which Eduardo doesn't like), but Gunther says this is not
> so: the value itself will be in the element content.
> 
> Arofan points out one possible problem, which is when there is structure in
> the value (e.g. exchange rate info). This might be solved by using mixed
> content, which no one likes. Eduardo says that this can be solved using new
> attributes or sibling elements.
> 
> In general, consensus that elements be used for data and attributes for
> metadata, as per Gunther's paper. One caveat from Arofan (no example given)
> is if metadata needs to have structure, in which case it has to use
> elements.
> 
> 7. Adjourn
>     Adjourned y:00.
> 
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-- 
Eduardo Gutentag               |         e-mail: eduardo.gutentag@Sun.COM
XML Technology Center          |         Phone:  (510) 986-3651 x73651
Sun Microsystems Inc.          |