1. A PPARC funded project Registry Type Hierarchy Paul Harrison IVOA Interoperability Meeting Cambridge MA 23-28 May 2004

2. 26 May 2004IVOA Interoperability Meeting: 1 Motto for the Registry WG? Taxonomy without representation is tyranny!

3. 26 May 2004IVOA Interoperability Meeting: 1 References Now Two concepts mixed Optional elements Title mandatory! Trying to express two mutually exclusive options

4. 26 May 2004IVOA Interoperability Meeting: 1 Refactored Reference Separate these in the type hierarchy Makes the intention clear Better object model

5. 26 May 2004IVOA Interoperability Meeting: 1 Reference Instance something http://somewhere.edu/ Or yyy x/x

6. 26 May 2004IVOA Interoperability Meeting: 1 Services use Resources

7. 26 May 2004IVOA Interoperability Meeting: 1 There is going to be distruption caused by these changes Get as many changes in as possible at one time Look at the type hierarchy Making that more complex (expressive!) has benefits for software binding tools Does not necessarily make the instance document tree depth greater

8. 26 May 2004IVOA Interoperability Meeting: 1 Comments on V10 Refactoring Generally good Schema smaller, concentrating on types. Unsure about The user experience writing instances with no substitution groups Believe that the type hierarchy could be richer. No clear indication where we expect/want extensions Want to try it out with some binding tools. Where is VODescription??