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Subject: Re: Fwd: [ubl-lcsc] Re: UBL, XMI, XSD, RSS, etc [on behalf of TonyCoates]
Dear Tim, I tried to post this to the LCSC list during the week, but OASIS doesn't let me post to their lists, so I thought I would just post it to you instead. Cheers, Tony. ** Forwarding message from "Anthony B. Coates" <abcoates@londonmarketsystems.com> on Tue, 27 May 2003 20:13:21 +0100 ** Reply to message from Tim McGrath <tmcgrath@portcomm.com.au> on Tue, 27 May 2003 09:53:55 +0800I 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. In terms of how UBL is designed now, using a spreadsheet, a having been playing around with a transitional approach as follows: 1. Use the spreadsheet as the source to generate a data model in XML. 2. Validate the XML data model against a restrictive XML Schema, and/or apply XSLT constraint checks, to check the consistency of the data model. 3. Generate the XML Schemas from the XML data model. This would give UBL the benefits of a well-controlled data model, while still preserving the spreadsheet. At a later stage, if people wanted to work with the XML data model directly, step 1 could be removed. I'm happy to discuss this approach further. It has certainly worked very well for MDDL. Cheers, Tony. ==== Anthony B. Coates London Market Systems Limited 33 Throgmorton Street, London, EC2N 2BR http://www.londonmarketsystems.com/ mailto:abcoates@londonmarketsystems.com Mobile/Cell: +44 (79) 0543 9026 [MDDL Editor (Market Data Definition Language), http://www.mddl.org/] [FpML Arch WG Member (Financial Products Markup Language), http://www.fpml.org/] ----------------------------------------------------------------------- This Email may contain confidential information and/or copyright material and is intended for the use of the addressee only. Any unauthorised use may be unlawful. If you receive this Email by mistake please advise the sender immediately by using the reply facility in your e-mail software. Email is not a secure method of communication and London Market Systems Limited cannot accept responsibility for the accuracy or completeness of this message or any attachment(s). Please examine this email for virus infection, for which London Market Systems Limited accepts no responsibility. If verification of this email is sought then please request a hard copy. Unless otherwise stated any views or opinions presented are solely those of the author and do not represent those of London Market Systems Limited. ==== Anthony B. Coates London Market Systems Limited 33 Throgmorton Street, London, EC2N 2BR http://www.londonmarketsystems.com/ mailto:abcoates@londonmarketsystems.com Mobile/Cell: +44 (79) 0543 9026 [MDDL Editor (Market Data Definition Language), http://www.mddl.org/] [FpML Arch WG Member (Financial Products Markup Language), http://www.fpml.org/] ----------------------------------------------------------------------- This Email may contain confidential information and/or copyright material and is intended for the use of the addressee only. Any unauthorised use may be unlawful. If you receive this Email by mistake please advise the sender immediately by using the reply facility in your e-mail software. Email is not a secure method of communication and London Market Systems Limited cannot accept responsibility for the accuracy or completeness of this message or any attachment(s). Please examine this email for virus infection, for which London Market Systems Limited accepts no responsibility. If verification of this email is sought then please request a hard copy. Unless otherwise stated any views or opinions presented are solely those of the author and do not represent those of London Market Systems Limited.
-- regards tim mcgrath phone: +618 93352228 postal: po box 1289 fremantle western australia 6160
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