[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: Are people really using Identity constraints specif ied in
Len, Don't knock those XML DTDs. You can only create small relatively simple things with them - saves people from injurying themselves and others. Same reason why you cannot buy automatic assault weapons (but I have mine back-ordered from Walmart for when the NRA manage to get that repealed!) It really must be Friday... DW Quoting "Bullard, Claude L (Len)" <len.bullard@i...>: > You have a declarative system that can dynamically > determine concepts from contexts? Or you have a > pattern matcher? Or you have a human making maps? > A registry is just another way to store apriori > agreements plus a map. > > Ummm... I have an RFP in front of me that requires we > deliver a DTD. Some subsumption is not yet complete. > > len > > > From: w3c@d... [mailto:w3c@d...] > > Bruce, > > Unfortunately schema was never intended to perform that role! > > Not the least because it has no context driven mechanisms. > > Apart from that - way too many people think it can do this 'magic' because > it > has been over sold - well beyond the original requirements the W3C started > from. > > We started off with a DTD - simple mission to describe the structure > permutations of an XML instance. XSD then subsumed that role. Snag is > neither > is able to deliver fully. It's all to easy to create an XML instance, or > set > of instances, that look perfectly reasonable and straightforward that is > darn > hard to then describe in schema. > > I'm reminded of the situation in England in the 1500's - when Latin was > still > the official legal language of law - but everyone uses English as the > working > language. The solution beckons ; -) > > DW. > > Quoting "Cox, Bruce" <Bruce.Cox@U...>: > > > In my world, attorneys speak "business rules" and IT folk speak "data > > constraints". Often, their intention and extension are identical. A > > really good schema is the membrane where these two sets touch each > > other, that is, it is equally successful from both points of view. > > > > > > Bruce B. Cox > > SA4XMLT > > +1-703-306-2606 > > > > -----Original Message----- > > From: Thomas B. Passin [mailto:tpassin@c...] > > Sent: Thursday, August 19, 2004 4:59 PM > > To: xml-dev@l... > > Subject: Re: Are people really using Identity constraints > > specified in XML schema? > > > > Roger L. Costello wrote: > > > > > - The value of the <minimum-age> must be an integer. This is a > > > constraint on the data. It will not change over time. > > > > Ha! What happens when the government decides that some relevant age is > > 67.5 years instead of 67? > > > > > Therefore, an XML Schema should simply constrain <minimum-age> to be > > > an integer. Higher level applications should implement the business > > > rule that <minimum-age> be further constrained to 16. > > > > > > How would you characterize the distinction between "business rules" > > > and "constraints on data"? > > > > A tricky, tricky issue - what is or is not a "business rule". I suspect > > that in practice most constraints that are not business rules are in > > place for supposed programming reasons, or by force of habit. > > > > In one project I work on, we have a data type that is a union of 1) an > > enumeration of strings, 2) a string that follows a certain regex > > pattern, and 3) an integer constrained to a certain range. No, don't > > bother to ask - it's one of those multi-agency reconciliations. > > > > -- > > Thomas B. Passin > > Explorer's Guide to the Semantic Web (Manning Books) > > http://www.manning.com/catalog/view.php?book=passin > > > > > > ----------------------------------------------------------------- > > The xml-dev list is sponsored by XML.org <http://www.xml.org>, an > > initiative of OASIS <http://www.oasis-open.org> > > > > The list archives are at http://lists.xml.org/archives/xml-dev/ > > > > To subscribe or unsubscribe from this list use the subscription > > manager: <http://www.oasis-open.org/mlmanage/index.php> > > > > > > > > ----------------------------------------------------------------- > The xml-dev list is sponsored by XML.org <http://www.xml.org>, an > initiative of OASIS <http://www.oasis-open.org> > > The list archives are at http://lists.xml.org/archives/xml-dev/ > > To subscribe or unsubscribe from this list use the subscription > manager: <http://www.oasis-open.org/mlmanage/index.php> >
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