Stefano Mazzocchi wrote: > > David BERNARD wrote: > > > Because metadata is only a point of view : metadata are data. > > I think David touched the key question: what should XIndice be concerned > about? > > In our recent XIndice wish-list thread, we identified the need for > having 'metadata' exposed by the database. > > I believe there are two kinds of metadata: > > 1) application level metadata > 2) database level metadata > > an example of the first is 'author' or 'workflow-status'. This doesn't > require changes in the DB if fully namespace-aware. > > examples of the second is 'modified-time', 'lask-accessed-time', 'id' > and all sorts of 'automatically-augmented' attributes. > > For the first class of metadata, I see any reason to expose it at this > level: Xindice is a DB engine, not an application provider. It's not its > concern to expose this data and as long as namespaced are handled > correctly, the application sitting on top has maximum freedom to use the > best scheme the want to store metadata. XNode was designed to be (a) simple, and (b) not require any changes whatsoever to Xindice or XML:DB. It's certainly possible to create an entire metadata layer/level and add complexity to Xindice (or XML:DB), but I felt that the best approach was something that was an add-on layer, something that could be ignored if unwanted, not extra baggage. It certainly could be used for either application- or database-level metadata, depending on how the metadata is designed (ie., XNode can be easily extended by adding either attribute or element content to its <xnode:Header> element.
I specifically didn't want to reinvent SOAP (which is hardly "simple" anymore, with new extensions coming out each month). Murray ........................................................................... Murray Altheim <mailto:murray.altheim@sun.com> XML Technology Center, Java and XML Software Sun Microsystems, Inc., MS MPK17-102, 1601 Willow Rd., Menlo Park, CA 94025 Corporations do not have human rights, despite the altogether too-human opinions of the US Supreme Court.
