[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: XML Data Modellling/Linking (was RE: AfterXQuery
On Fri, 22 Oct 2004 21:15:54 GMT, rpbourret@r... <rpbourret@r...> wrote: > Michael Kay wrote: > > > What happened to the old doctrine of data independence? > > Hmmm... Sounds like the relational model. (Sorry, couldn't resist.) > > I think this could actually be dealt with at the query language level, I hope you're not joking :-) The CODASYL data model ultimately foundered because of its unwieldy links, and XLink foundered trying to do something similar for XML. Maybe the lesson here is that the relational model approach of defining links *dynamically* based on relationships on the *values* of information items rather than predefined links really is the way to do what XLink tried to do. The thing I always liked best about XQuery is simply the addition of a Join operation into the XML corpus. Until this thread I hadn't thought of this as a replacement for XLink, but that idea is starting to take root in my head ... it really might be worth a look back at the struggle between advocates of CODASYL and those for the relational model to see if there is a lesson there for us. Date's little book called "The Database Relational Model: A Retrospective Review and Analysis : A Historical Account and Assessment of E. F. Codd's Contribution to the Field of Database Technology" is the best summary of this that I know of ...and the fact that Date and friends are fervent opponents of XML should not dissuade us from carefully considering his analysis :-) > Liam Quinn wrote: > I actually think XQuery has so far failed to address its > requirement of supporting pointers/links, Maybe that will turn out to be a Good Thing. The question in my mind is not the thread-starter "what comes after XQuery" but whether the true power at the core of XQuery will remain visible and viable amidst the feature bloat and consequent delays of the spec itself. Potentially, this ability to do linking based on dynamic value relationships could be XQuery's (or XQuery-minus-minus's ) greatest contribution.
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