Converging the Data Models
brian.thomas at gsfc.nasa.gov
Thu Sep 16 07:46:35 PDT 2004
On Thursday 16 September 2004 05:58 pm, Jonathan McDowell wrote:
> First, some observations:
> - The objects in Char are very close to the concepts elaborated in STC,
> but Char redefines these because Francois and Mireille don't want the
> Char definition to be dependent on the complexities of STC.
> - Elements in Arnold's schema are very similar to Quantity, but
> don't use the Quantity schema.
> The problem here is that each schema is so big, when done right,
> that it's hard to buy in to it. But we must reuse components rather
> than all go off in separate directions. So I have a proposal for converging us:
Tis true that these are large schemas, the STC in particular. But I thought
the solution was to use "xincludes" in the XML documents to get around
having to put in the full blown description. In that fashion
one only defines their coordinates once at the beginning (or in another
document) and includes them.
Another thought is that the "Toy" schema can be build such that they define
the simple structures they include in terms of the "full" schema. For example, a "toy"
STC would have a "J2000" complexType which inherits from complexTypes
in STC, but has restrictions on it that make it very simple when it is instanciated.
This sort of thing is machine parsable...I've taken a stab at it in the Q Java package
I wrote..I use something like this mechanism to define the "trivialQ" out of the
atomicQ (e.g. "trivialQ" isa restricted AtomicQ where the restriction is that its
always of scalar, unitless, coordinateless, string value).
* Dr. Brian Thomas
* Dept of Astronomy/University of Maryland-College Park
* Code 630.1/Goddard Space Flight Center-NASA
* fax: (301) 286-1775
* phone: (301) 286-6128 [GSFC]
(301) 405-2312 [UMD]
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