[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

Re: Restrictions on existence of attributes?

• To: Rick Jelliffe <rjelliffe@a...>
• Subject: Re: Restrictions on existence of attributes?
• From: Robin Berjon <robin.berjon@e...>
• Date: Tue, 27 Jun 2006 12:59:08 +0200
• Cc: Howard Bartel <hbartel@c...>,"xml-dev@l... Developers" <xml-dev@l...>
• In-reply-to: <44A0C8DD.2060105@a...>
• References: <CPEELKNOKCDGNPIPEIAFEEPKEIAA.hbartel@c...> <44A0C8DD.2060105@a...>

> Howard Bartel wrote:
>> On Jun 27, 2006, at 07:57, Rick Jelliffe wrote:
>> How do I specify that an element MUST have ONLY ONE of a set of  
>> possible
>> attributes?
>> I understand that there is a "choice" option but it seems that  
>> this only
>> applies to elements, not attributes within an element.
> If you are using XML Schemas, then look at the "enumeration"  
> "facet" of "datatypes". Your element must be a "complex type".

I don't think that'll solve Howard's problem since he wants only one  
of a set of attributes, not only one of a set of attribute values.  
Presumably this can always be remodelled with some indirection (e.g.  
having a @name attribute which is an enumeration, and an @value which  
would give its value), but that might not be an option.

My XML Schema is getting very rusty since I don't get to use it much  
anymore, but I don't think it can be done (or if it can it involves  
dark magic). In RelaxNG it's just a <choice> of <attribute> elements,  
easy as ¹.

-- 
Robin Berjon
    Senior Research Scientist
    Expway, http://expway.com/

• References:
  • Restrictions on existence of attributes?
    • From: "Howard Bartel" <hbartel@c...>
  • Re: Restrictions on existence of attributes?
    • From: Rick Jelliffe <rjelliffe@a...>

• Prev by Date: Re: Help! Any ideas for language for validating links?
• Next by Date: Getting some nice XML-RSS feeds going...
• Previous by thread: Re: Restrictions on existence of attributes?
• Next by thread: Getting some nice XML-RSS feeds going...
• Index(es):
  • Date
  • Thread