Use Cases for new Registry search interface
paul.harrison at manchester.ac.uk
Mon Jun 6 04:51:35 PDT 2011
On 2011-06 -06, at 11:28, Markus Demleitner wrote:
> Coming back from vacation, I've added some comments to the wiki page
> and added what I think Paul's point are in two places -- so, Paul, if
> I misrepresented you, sorry.
I was serious about providing a formal definition of the registry data model in a form other than the XML schema - but I tend to agree that these schema should define the interchange format at least so that part of the registry infrastructure does not change - this was actually at the heart of the different interpretations that various groups placed on these schema historically and the reason why there was no universally accepted searchable data model definition.
I have even taken a step on the path to creating an independent definition of the model using the vo-urp (http://code.google.com/p/vo-urp/) formalism developed by Gerard Lemson et.al. I have used a semi-automatic reverse engineering of the existing schema to produce the MagicDraw XMI UML model
This model is fairly comprehensive with one exception - xml types that are derived from primitives such as xs:integer are not yet represented. This needs more work, but I am currently busy with my "day job".
The issues going forward on this are
1. The relational table model that will naturally come out of this will result in many joins being needed for fairly "simple" queries.
2. The xml representation of the model from vo-urp will not be exactly the same as the original schema.
I think that the first of these issues can probably be somewhat mitigated by some manual tweaking of the model (Gerard has experience of this from the theory work) - and perhaps by providing some standardized views and adql functions. The second can probably be dealt with by some standardized xsl transformations.
Anyway I think that it is worth carrying on with this approach to see if it can produce an acceptable model with its associated relational and XML representations.
More information about the registry