Greg Woodhouse wrote:
> Now, in the project I'm currently working on it is
> necessary to define mappings between these schemas and
> relational tables. This turns out to be fairly
> complicated because the data models on either must
> satisfy different constraints and semantic
> requirements that only make sense at the object level
also complicated because object models are usually hierarchical;
relational databases do not natively deal well with hierarchies.
> and above rather than at the attribute level. If I
> understand correctly, the protocol used in a lab test
> could impose a constraint that doesn't make sense at
> the level of individual measurements, but at a higher
> level of abstraction.
Certainly true. That's the nature of object models...
> But, again speaking as a layman,
> I can't imagine that you'd want to map elements when
> the protocols are different, but you might want to
> keep track of the degree of "conceptual similarity"
> between two results, and constraints requiring that a
> specific protocol be used.
You might, if you could determine that the protocols were equivalent, or
else there were well-known conversion rules for the data generated by
one clinical protocol into values for another protocol. But this might
be difficult territory in any case...
- thomas beale
