RE: Beta 4

Hello all,

As you can see from the comments below I sent an email in January regarding
support for key and keyref in the XML Schema - been a bit busy since. The
background is that we are using XML Schema to define a RDBMS datamodel.
We're using individual XML entities for tables (containing columns etc). We
were evaluating XML Spy Beta to use as an editor for the individual XML

The key/keyref items would seem to come in useful where we are dealing with
things like foreign keys. Given that the datamodel contains all of the
individual tables, I was hoping to use a key/keyref pair to have the
foreign key validated to ensure that the table that the foreign key entity
refers to does exist in the model. Likewise for indices, data types and
validation rules. In the end we have created separate simpleTypes for the
validation, where each simpleType is simply an enumeration of the valid
options. These are contained in a separate schema file which is included
into the main schema. We just regenerate the validation schema as required.

I guess we could look at ID and IDREF as an alternative, but the key/keyref
pair seemed made for our purpose. I'm also looking to use the unique item
to ensure that table names are unique - and so on.

I don't subscribe to the mailing list, so if anyone has any suggestions or
feedback please respond directly to me at

Kind Regards,
Andrew Rickard

                    Alexander"           To:     "''" <>             
                    <        cc:                                                                       
                    m>                   Subject:     RE: Beta 4                                                   

Dear beta tester,

we have currently not implemented unique/key/keyref in XML Spy 3.5, because
this aspect of XML Schema is not being used by most of our customers and
beta testers so far.

Once the W3C advances XML Schema to Proposed Recommendation status and it
still includes these identity-constraints, we will certainly be supporting
this in XML Spy, but this process may take some time.

As a member of the W3C XML Schema Working Group, I would, however, like to
ask you for some help in this matter:
the W3C XML Schema Working Group did not receive nearly enough feedback on
these aspects of XML Schema during the Candidate Recommendation Period to
judge if the identity-constraints currently available in the Candidate
Recommendation are suitable for schema authors and users.

It would, therefore, be very important for the XML Schema Working Group to
receive further feedback regarding the use of unique/key/keyref
identity-constraints from schema authors and users. If you are using these
aspects of XML Schema and consider them important for your work, please
submit an e-mail to

and describe your use-case and why you require such capabilities for your
schema work. If possible, please do also include a sample XML Schema with
your posting that will give the XML Schema Working Group additional
feedback. Also, please do indicate whether any enclosed schema may be used
as part of an upcoming conformance test suite.

This will help the XML Schema Working Group decide whether the current
identiy-constraint mechanism is being used or if there are problems
involved that may require this feature to be dropped from the language for
the time being.

Thank you,


... Alexander Falk
... President, CEO of Altova, Inc. - The XML Spy Company
... Member of the W3C XML Schema Working Group
... Member of the W3C Advisory Committee

XML Spy 3.0  -  the first true Integrated Development Environment for XML
Visit to download a free 30-day evaluation version

-----Original Message-----
From: []
Sent: Tuesday, January 16, 2001 10:13
Subject: Beta 4

I've just downloaded the latest beta for version 3.5, and was disappointed
to see that support for the key and keyref items is still not available -
are there plans to provide this support and if so when?

Congratulations to your team on a good product.

Kind Regards,

Andrew Rickard.

Received on Wednesday, 7 March 2001 05:17:11 UTC