XML DTD vs. XML-Data

[Jeff Greif]

1.  You can do enumeration-based validation using attributes in your DTD,
e.g.
<!ELEMENT primary_colour EMPTY>
<!ATTLIST primary_colour   name (red|blue|green) "red">

You might be able to use one of the schema proposals (XSchema, SOX, DCD
which probably supersedes XML-Data), but I think they're all weak in this
area from my limited skimming of their current drafts.  The RDF proposal
certainly has the power to handle all kinds of data typing, but RDF is
pretty complicated.

2.  Different schema proposals had different goals in respect to
convertibility back and forth to DTDs.  Ron Bourret's excellent slide show
(with extensive annotations) discusses these issues.  See the presentation
at:

   HTML:


http://www.informatik.tu-darmstadt.de/DVS1/staff/bourret/xml/xmlschemas/inde
x.htm

   PowerPoint:


http://www.informatik.tu-darmstadt.de/DVS1/staff/bourret/xml/xmlschemas/XMLS
chemas.ppt

Jeff


-----Original Message-----
From: Tiago Moitinho de Almeida <tma at chiron.pt>
To: XML Dev <xml-dev at ic.ac.uk>
Date: Thursday, February 18, 1999 9:22 AM
Subject: XML DTD vs. XML-Data


...
>1.
>Two important issues about the validation are:
>- data type checking (ex: the content of <date> tags should have a valid
date
>format)
>- validity domains  (ex: for the content of <primary_colour> I should only
>accept "blue", "red" or "green").
>
>As far as I undertand, XML-Data provides solution for the 1st issue, and I
can
>work arround it in a DTD using a #FIXED attribute for those element
>declarations.
>
>However, I don´t see how XML-data or XML DTD provide information to meet
the 2nd
>issue.
>
>
>2.
>2 questions about XML DTD's and XML-Data:
>- Can I use DTD to do everything that XML-Data does?
>- Using XML-Data, can I somehow get rid of XML DTD's?
>



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