Copyright (c) 2001 Rick Jelliffe, Topologi Pty/ Ltd

The Resource Description Framework is the cornerstone of the W3C's Semantic Web Activity. This schema gives some constraints for XML data validation purposes.

RDF has four anti-standard behaviours, due doubtlessly to the lack of discipline using a schema language would have bought.

First, it supports an open-ended number of attributes in the abbreviated syntax, rdf:_1 to rdf:_n.

Second, it does not follow the usual rules for namespaces, so that if <rdf:* xxx="..."> if assumes we can also go <y:z rdf:xxx="...">

Third, capitalization rules are difficult to remember, and, even when you can, frequently examples get them wrong.

Fourth, the not all RDF namespace elements are defined in the RDF document, but crop up in the RDFS document. These include rdf:Property.

All in all, the current RDF Recommendation is utterly unsatisfactory, and needs to be revised soon. All that being said, there is some good tutorial material, and if everyone tries to follow standards, it may work interoperably one day.