- W3C standard (Guide,
- Defining concepts & relationships within area of knowledge
- Not unlike a DBMS data dictionary, but ..
- Global, standard syntax based on RDF
- Using URIs as keys
- More easily extensible structure
- On the Web
- and ...
- Includes standard vocabulary for describing properties
- datatypes (e.g., integer, date, string ..)
- relations (e.g. subclass of, property of ..)
- cardinality (e.g. exactly one ..)
- characteristics of properties (e.g. symmetry)