Re: Fwd: [ubl-lcsc] Re: UBL, XMI, XSD, RSS, etc [on behalf of TonyCoates]

["Monica J. Martin" <monica.martin@sun.com>]

>
>
>>><<I actually see the value of the UML within UBL in two ways:
>>>firstly, as a means of describing a conceptual model from which many 
>>>physical models (various document, eg. Purchase Order, of various 
>>>syntaxes, e.g. EDIFACT or XSD) can be generated (as Steve says).
>>>    
>>>
>>Yes, that is definitely the advantage of having a logical data model.  However,
>>let me add my own experience here.  I've recently been looking at the ISO/SWIFT
>>method of generating XML Schemas from UML, which is used for ISO 15022.  They
>>use a very restricted set of UML constructs in order to maintain the
>>consistency of their model, which is a good idea.  Like most general modelling
>>paradigms (including XML Schema), the fewer features you use, the more
>>manageable your model tends to be.
>>
>>The problem, though, is that conformance to the ISO/SWIFT UML usage is
>>essentially voluntary, because UML tools don't provide an easy way to control
>>the "style" of a UML document.  There is no UML Schema language.  For this
>>reason, when MDDL decided to move to a logical model for generating its XML
>>Schemas, I chose not to use UML.  Instead, I wrote a simple XML Schema for the
>>*logical* model.  This is quite different to the MDDL Schema that people use
>>for financial information.  The MDDL modelling Schema is used to create a
>>tightly constrained XML view of the logical model.  This makes it easy to
>>maintain the "style" of the logical model, which greatly benefits the quality
>>of the results.  As well as applying a restrictive XML Schema to the logical
>>model, we also use some XSLT stylesheets to check constraints that XML Schema
>>cannot check.
>>
>>If at any stage we get sufficient requests for a UML model, we will generate an
>>XMI model from the MDDL data model.  At the moment, we find that a suitably
>>generated set of Web pages makes the information accessible to the people who
>>want to review the model without looking at XML directly.
>>
>>So, the point I want to make is that it is a very good idea to have a logical
>>data model.  You can use UML for this, but it isn't the only option.  What is
>>more important is being able to constrain the logical model to maintain
>>consistency and quality.>>
>>

mm1: To your point, and in a similar circumstance, ODETTE is working to 
define a global data model.  Uses UML.  Has placed
a specific set of constraints to generate XMI and then results in XML 
Schema (Note: The constraints ensure the result is a consistent logical
data model - given you can get different results with different tools 
using different XML Schema design preferences).

There are other options, yes....
Monica