W3C home > Mailing lists > Public > xmlschema-dev@w3.org > November 2007

RE: XSD with keys... what to use in Java to process XML?

From: Michael Kay <mike@saxonica.com>
Date: Tue, 20 Nov 2007 00:04:52 -0000
To: "'dave'" <ceek63@yahoo.com>, <xmlschema-dev@w3.org>
Message-ID: <028d01c82b08$fa0910d0$6501a8c0@turtle>

You need to say what your requirements are. Saying that your requirement is
to "leverage" your schema seems an odd way of expressing it.

I don't know of any technology that enables you to use key/keyref
definitions for anything other than validation. If you want to use keys for
navigation, use XSLT, with local key definitions within your stylesheet.
There's no reason why these should bear any relationship to the keys used
for validation. If you want to get maximum value from your schema, you can
use schema-aware XSLT. I don't think any current schema-aware XSLT
processors will exploit the key/keyref definitions for strong typing or
optimization, but it's certainly not beyond the bounds of what's possible in

Michael Kay

> -----Original Message-----
> From: xmlschema-dev-request@w3.org 
> [mailto:xmlschema-dev-request@w3.org] On Behalf Of dave
> Sent: 19 November 2007 20:12
> To: xmlschema-dev@w3.org
> Subject: XSD with keys... what to use in Java to process XML?
> If you've an XSD with key/keyref constraints, what is the 
> best XML parsing (JAXP vs JAXB) method to use in Java?
> I did some reading on this. I was inclined to use Java-XML 
> binding frameworks to leverage my XSD. But JAXB 1.0 doesn't 
> support key/keyref (meaning doesn't support validation?? not sure).
> Also not sure if JAXB 2.0 supports it.
> OR should I use JAXP instead?
> Parsing performance is not an issue for my application.
>   I know key/keyref constraints' use at the XSD  level.
>   Can you access these key/keyrefs at the Java
>   application level?
>   For e.g. I need to find the number of Keyrefs
>   referencing the Key in my Java app?
>   Basically, I am trying to understand if I can
>   leverage these constraints at the Java level (like
>   accessing selector/field values, xpath expressions,
>   etc).
>   Or are these constraints are only used at the XSD
>   level and XML validation?
>   In short, how would one leverage these key/keyrefs  at the 
> Java application level?
>   Thanks for any pointers.
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Received on Tuesday, 20 November 2007 00:05:10 UTC

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