Re: Object Role Modelling (ORM) or UML or ?? for designing Schemas

[Dave Carlson <dcarlson@ontogenics.com>]

Hello,
I'd like to clarify one point before commenting.  By "approaches of UDDI,"
I assume that you are referring to the white paper that I wrote on modeling
UDDI schema with UML.  These are not approaches of UDDI per se, but rather
conventions that I follow when using UML to model schemas. The UDDI was
just one example of this.

The use of UML attributes vs associations to other classes are both
perfectly valid models in UML.  The mapping that I use for UML to schema is
based on the OMG specification of XMI, which defines a complete UML to DTD
mapping.  I've adapted this for a mapping to XSD, then I proposed a set of
UML stereotypes and tagged values (based on XML Schema) that allow
customization of the mapping, starting with the XMI mapping as a basis. The
Rational white paper had a much more limited UML profile based on DTD. (I
am preparing a new white paper that contains the full UML profile
description for my proposal.)

My suggestion for best practices is to use UML attributes for properties
having simple datatypes, and to use associations to other complexTypes.  I
find that this lead to *much* more readable UML diagrams compared to using
assoications for everything.  One of my primary goals in using UML do model
schemas is to improve our ability to communicate the conceptual models with
non-XML-savvy stakeholders.

I do occassionally use UML attributes with a UML class as its type (also
valid in UML). In that case the attribute type is a XSD complexType.  I
have found this to be useful in limited situations where the complexType is
a simple struct (e.g. Money that has two attributes for amount and
currency).  For example, I used this approach in the UDDI white paper to
model a complexType named "StringI18N" that was a string with an xml:lang
attribute.

Regards,
  Dave

----- Original Message -----
From: "Inga Eckermann" <inga.eckermann@profi-consult.de>
To: <xml-dev@xml.org>
Sent: Monday, February 12, 2001 7:44 AM
Subject: Object Role Modelling (ORM) or UML or ?? for designing Schemas


Hello,

I would like to hear, which modelling languages and/or methods you use when
developing Schemas.
In an article "Object Role Modelling and XML-Schema" was written that the
data modeling support is richer than other notations, i.e. UML.
My first thought is, that it has more advantages to stick to a widely used
modelling language like UML particularly as the ORM-Diagram is quite
confusing when complex relations are expressed.

But the approaches of UDDI and the Specification from Rational seems to be
different.
For example, elements of one complexTpye are displayed in Rational
specification as role-names and  in UDDI they are either attributes
(simple) or other classes which are
linked with an association.

I would be glad, to hear from best practices, experiences and maybe other
ressources about this topic.
Thank you!!

Mit freundlichen Grussen von
Inga Eckermann
ProFI Consult Gesellschaft fur Unternehmensberatung mbH
-Anwendungsmanagement-
Rendsburger Str. 34 * 30659 Hannover
Tel.: 0511-9020-308
mailto:inga.eckermann@profi-consult.de