Hi Simon That looks better. I'd still like to see an even simpler introductory diagram, if that is possible, which while not showing 100% of XML Schema constructs, shows enough to give the user a good idea of the key schema objects involved. The existing diagram in draft 31 section 5, but with the 'dimension' box removed, is very attractive to first time users. It introduces elements which can be of simple type or complex type, the latter consisting of a group being either sequence or choice, which contains a sequence of elements or wildcards. Note no mention of particles at this point. It may not be possible to accomodate such a simple diagram with the full diagram without contradictory terminology? But I think we should try. FWIW I use a very similar diagram to explain the IBM MRM model to first-time users. Regards, Steve Steve Hanson WebSphere Message Brokers Hursley, UK Internet: smh@uk.ibm.com Phone (+44)/(0) 1962-815848 "Simon Parker" <simon.parker@polarlake.com> Sent by: dfdl-wg-bounces@ogf.org 07/02/2008 11:54 To <dfdl-wg@ogf.org> cc Subject [DFDL-WG] DFDL Schema abstract data model 4 Good morning. As discussed yesterday, here is a fresh version with improvements and corrections applied. I added a note to the Discussion section, reproduced here for convenience. --- Yesterday's conference expressed the view that the version 3 model contained more detail than was useful. Version 4 removes some of the new abstractions to bring it closer to version 2, but retains most of the relationships. The new naming conventions (Global*, *Reference, *Definition) didn't find favour, and this version uses established names for abstractions discussed in the XML Schema specification. Other changes correct errors and misunderstandings: only simple types may have explicit base types; DFDL doesn't support All groups or explicit Group constructs in groups; some associations were incorrectly described as aggregations. Dfdl annotations can be used at any annotation point. There are some restrictions, but this model cannot show details clearly so they are left for a different form of presentation or for later addition. --- Regards, Simon Simon Parker Software Consultant PolarLake 80 Harcourt Street Dublin 2, Ireland Phone +353 1 449-1075 Fax +353 1 449-1011 Web http://www.polarlake.com/ The information transmitted in this email is intended for the addressee only and may contain confidential and/or privileged material. Any review, retransmission, dissemination, reliance upon or other use of this information by persons or entities other than the addressee is prohibited. If you think, for any reason, that this message may have been addressed to you in error, we would ask you to notify the sender immediately by return email and delete the material. PolarLake Limited | Registered in Dublin, Ireland | Number 357324 | Registered office as above. -- dfdl-wg mailing list dfdl-wg@ogf.org http://www.ogf.org/mailman/listinfo/dfdl-wg Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU