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

Re: Schema question

• To: ht@c... (Henry S. Thompson) ht@c...
• Subject: Re: Schema question
• From: Vladimir Perlov <vladperl@s...>
• Date: Thu, 12 Jun 2003 11:05:45 -0400
• Cc: lists.xml.org <xml-dev@l...>

The elements in the group "all" may appear once or not at all. 
In this case I think appropriate solution is to use "choice" group element.

> "Nada Reinprecht" <Nada_Reinprecht@n...> writes:
> 
> > The problem is:
> > there are a, b, c and d entities that can be represented with the same type
> > x
> > there is e entity that can be represented with type y which is derivation
> > of type x.
> > there is need to identify a, b, c, d and distinguish between them
> > all these entities are used in the same transaction where any combination
> > of entities is allowed
> > options:
> > 
> > 1.use elements a type x, b type x, c type x, d type x and e type y; place
> > them in the transaction as optional elements; the solution is clean but
> > requires rigid order of elements in the transaction.
> 
> This is the correct solution in my opinion -- if order does not encode
> any information, then imposing an arbitrary order is good, not bad -- leaving
> order unconstrained encourages people to suppose that perhaps 
> 
> <container>
>  <a>...</a>
>  <b>...</b>
> </container>
> 
> actually means something different from
> 
> <container>
>  <b>...</b>
>  <a>...</a>
> </container>
> 
> However, this is an FARP (Frequently Asserted Religious Position), and
> if you're not a devotee, you can use an <all> group to allow any
> order, e.g.
> 
>  <xs:all>
>   <xs:element name="a" type="my:x" minOccurs="0"/>
>   <xs:element name="b" type="my:x" minOccurs="0"/>
>   <xs:element name="c" type="my:x" minOccurs="0"/>
>   <xs:element name="d" type="my:x" minOccurs="0"/>
>   <xs:element name="e" type="my:y" minOccurs="0"/>
>  </xs:all>
> 
> ht
> -- 
>   Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
>                       Half-time member of W3C Team
>      2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
> 	    Fax: (44) 131 650-4587, e-mail: ht@c...
> 		     URL: http://www.ltg.ed.ac.uk/~ht/
>  [mail really from me _always_ has this .sig -- mail without it is forged spam]
> 
> -----------------------------------------------------------------
> The xml-dev list is sponsored by XML.org <http://www.xml.org>, an
> initiative of OASIS <http://www.oasis-open.org>
> 
> The list archives are at http://lists.xml.org/archives/xml-dev/
> 
> To subscribe or unsubscribe from this list use the subscription
> manager: <http://lists.xml.org/ob/adm.pl>
> 

• Prev by Date: Re: Market-driven vice Committee-driven technology evolution
• Next by Date: Create XML
• Previous by thread: Re: Market-driven vice Committee-driven technology evolution
• Next by thread: Create XML
• Index(es):
  • Date
  • Thread