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

Re: How to specify validation properties in DTDs?

• From: Chris Maden <crism@o...>
• To: xml-dev@i...
• Date: Tue, 24 Mar 1998 10:18:45 -0500

[Parik Rao]
> Hi, I'm trying to figure out how do I do parameter validation in my
> DTD.  For example, I have an element which specifies a SIZE as an
> attribute.  I'd like to enforce certain rules : the charaacter data
> in size is digits and the size is always less than 1,000,000 (for
> example).  As far as I can figure out, there is no way to do this!
> E.g.
> 
> <ATTLIST MYELEMENT
> 	SIZE CDATA #REQUIRED
> >
> 
> Well, how do I set validation parameters for size?  I tried to play
> around with entity but really couldn't come up with anything:
> 
> <!ENTITY % NUMBERONLY ...now I'm stuck>
> <!ATTLIST MYELEMENT SIZE %NUMBERONLY;>
> 
> Anyone done this sort of thing?  Is this sort of validation beyond
> the scope of DTDs?

On the nose: this is beyond the scope of DTDs.

This kind of restriction must be specified as an application
restriction, and enforced by means outside the current scope of XML.
A stylesheet might be able to check the attribute value, and throw an
error if it doesn't conform (if the XSL WG decides to have error
handling); an XML application could check this information after the
parser parses the data.

There's also work ongoing about XML-Data, which would permit you to
specify restrictions like this.  However, it's not done (or close, I
think).

-Chris
-- 
<!NOTATION SGML.Geek PUBLIC "-//Anonymous//NOTATION SGML Geek//EN">
<!ENTITY crism PUBLIC "-//O'Reilly//NONSGML Christopher R. Maden//EN"
"<URL>http://www.oreilly.com/people/staff/crism/ <TEL>+1.617.499.7487
<USMAIL>90 Sherman Street, Cambridge, MA 02140 USA" NDATA SGML.Geek>

xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i...
Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/
To (un)subscribe, mailto:majordomo@i... the following message;
(un)subscribe xml-dev
To subscribe to the digests, mailto:majordomo@i... the following message;
subscribe xml-dev-digest
List coordinator, Henry Rzepa (mailto:rzepa@i...)

• References:
  • How to specify validation properties in DTDs?
    • From: Parik Rao <parikr@p...>

• Prev by Date: Re[2]: Relational Tables and structured document
• Next by Date: Re: Relational Tables and structured document
• Previous by thread: How to specify validation properties in DTDs?
• Next by thread: An example of database query result in XML
• Index(es):
  • Date
  • Thread