W3C home > Mailing lists > Public > xmlschema-dev@w3.org > November 2002

Re: XML Schema Design Patterns: Avoiding Complexity

From: Dan Vint <dvint@mindspring.com>
Date: Thu, 21 Nov 2002 09:45:25 -0800
Message-Id: <5.1.0.14.2.20021121093758.00a7cfa0@mail.dvint.com>
To: <xmlschema-dev@w3.org>

Interesting set of Do's and Don'ts. I see several items listed as implement 
carefully. Has this set only been considered as individual items, or have 
they also been evaluated in the context of having a schema that uses all of 
them.

Seems to me that you might easily work with one or two of the "careful" 
items and still have a manageable schema, but try and use all the 
recommendations together and the complexity returns.

I didn't see a statement of whose complexity we are considering - is it the 
tools and parsers or complexity in terms of the human trying to implement? 
For instance I have had problems with complexType definitions that are 
fairly easy to follow by hand, but when these are nested several tools 
loose the ability to detect duplicate attribute declarations that occur due 
to inheritance. This would be a type based upon another type nested 3 
layers deep.

The use of substitution groups are impossible to try and manage by hand in 
a schema over 20 elements in size, but maybe is easy for the parser to deal 
with. We haven't used these much so I don't know how well the tools support 
this (or report what elements would now be allowed that you might not be 
thinking of).

..dan

At 07:19 PM 11/20/2002 -0800, Dare Obasanjo wrote:

>http://www.xml.com/pub/a/2002/11/20/schemas.html
>
>The above link is to an article just published on XML.com on working with 
>W3C XML Schema which is part guidelines on how best to use the language 
>while avoiding getting bogged down in the complex bits and part response 
>to Koshuke Kawaguchi's article at 
>http://www.xml.com/pub/a/2001/06/06/schemasimple.html
Received on Thursday, 21 November 2002 13:06:17 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 11 January 2011 00:14:35 GMT