OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help



   RE: [xml-dev] fundamental facets - inquiry from the XML SchemaWorking Gr

[ Lists Home | Date Index | Thread Index ]

Eric and Dare are both right here, depending on your perspective.

As I understand Eric, he wants to use the data types of the programming 
language he uses or of the databases in which data is stored. Because these 
systems already have well-defined types, any mismatch between their types 
and the types of XML Schema get in the way.

As I understand Dare, he wants to be able to do "Native XML Programming", 
using systems base directly on the built-in types of XML Schema. Most 
databases and programming languages have a set of built-in types, and many 
optimizations are based on knowledge of these types.

Actually, this is one of the real advantages of the facets approach taken 
by XML Schema. You can define new types based on existing ones - if you 
need an integer that can only be a certain size, you use facets to express 
that. Any system that can handle the more general type can also handle the 
specific one. But what if you want to specify new types that are not 
derived from existing ones?

Many databases allow new types to be created with 'data blades' or 
'extenders' or whatever. As Dare points out, this requires specification of 
the operations on these types - how do you compare two instances? how do 
you serialize an instance? how do you construct an instance from a 
serialized format? I'm not convinced that MathML is the right language for 
doing this, but such a language could be devised. However, the problem 
turtles. The specification of these operations needs to be done in terms of 
SOMETHING, which brings us back to the set of types known in the language 
used for specifying the operations.

So what advantage would that have over doing it directly in W3C XML Schema?



News | XML in Industry | Calendar | XML Registry
Marketplace | Resources | MyXML.org | Sponsors | Privacy Statement

Copyright 2001 XML.org. This site is hosted by OASIS