Reference implementations
Mireille Louys
mireille.louys at unistra.fr
Tue May 10 18:32:06 CEST 2016
Hi Gerard, Hi all,
Le 10/05/2016 18:04, Gerard Lemson a écrit :
> HI Tom
> I think that writing a model in VO-DML is *not* an implementation of
> the model, but its definition. It *is* an implementation of VO-DML,
>
Yes, I agree.
> An *instance* of the model is a valid implementation of the model, but
> we have no generic standard way (yet) for representing instances of
> data models. The mapping document will fit that, but protocols can
> also do that.
> Showing interoperability of the data model could be an application
> that uses two or more independent instances of the data model
> serialized in some standard way.
> One way this might happen is that votables annotated with the same
> data model are interpreted as instances of the data model.
> And it would be nice if something interesting is done with them.
> Ieally this could be an implementation of a use cases the model was
> supposed to support.
The different scenarios proposed in the use-cases should be checked , I
guess.
This is sometimes difficult if the model tries to encompass many
different situations ( as Char tried, and ND-Cube will probably) .
Could we envisage a partial validation where the main scenarios are
checked first and the secondary ones later.
In other terms , should we be happy with a 75% validation rate for
serialisations obtained from a new data model?
my 2c, Mireille.
> Gerard
>
>
> On Tue, May 10, 2016 at 10:46 AM, Tom McGlynn (NASA/GSFC Code 660.1)
> <tom.mcglynn at nasa.gov <mailto:tom.mcglynn at nasa.gov>> wrote:
>
> If you feel that data models are not subject to the requirement of
> two reference implementations, that's fine but then this
> discussion is moot regardless. If you think they are then you are
> quibbling about my choice of words. Feel free to substitute
> whichever you like for 'protocol'.
>
> Regards,
> Tom
>
> Matthew Graham wrote:
>
> But a data model is not a protocol.
>
> -- Matthew
>
> On May 10, 2016, at 4:37 PM, Tom McGlynn (NASA/GSFC Code
> 660.1) wrote:
>
> This kind of using the fact that you have written a
> definition of the model counting as an implementation of
> the model sounds awfully incestuous. I have always read
> the requirement as having two different groups using the
> protocol in some service, ideally one that supports doing
> astronomy.
>
> Tom McGlynn
>
> Matthew Graham wrote:
>
> So once we have a mapping standard with reference
> implementations any DM model specified in VO-DML could
> automatically have a reference implementation
> (according to these criteria) which would make life
> easier. Time to get that mapping spec out :)
>
> -- Matthew
>
>
>
> On May 10, 2016, at 4:00 PM, Laurino, Omar wrote:
>
> Hi,
>
> I agree with Gerard that items 1) and 2) look like
> the same, unless one brings in a standard for
> instance serializations. Since we can have
> standardized mapping strategies (as different
> recommendations) that map instances of valid
> VODML/XML models and their standard
> serializations, I don't think a valid
> serialization of an instance should be required
> for data models: this should be guaranteed by the
> mapping standard(s) and their reference
> implementations.
>
> As for the ModelImport requirement, it makes sense
> for "low level" models but not for "high level"
> ones, plus there is no way to guarantee that all
> types defined by a model are extendable/usable by
> other models. It gets too complicated.
>
> I would suggest we include the "model import"
> evidence as a "soft requirement", to be evaluated
> on a case-by-case basis depending on the use cases
> of the model. For STC, it makes a lot of sense to
> require this additional proof of interoperability,
> because the model is intended to be a building
> block for other models.
>
> Or, we might be to *require* that at least one
> reference implementation is a
> mission/archive/service-specific model that
> extends the standard one. So, if we had a model
> for Sources/Catalogs, at least one reference
> implementation should be a
> mission/archive/system-specific model that proofs
> the model can be meaningfully extended by actual
> specializations. Other than properly validating as
> VODML/XML, this model should be evaluated for its
> domain-specific content, and that's probably not
> something you can automate. This should also be a
> good way to involve implementors from the
> community, so it's probably my preferred one.
>
> Omar.
>
>
> On Tue, May 10, 2016 at 9:38 AM, Gerard Lemson
> <gerard.lemson at gmail.com
> <mailto:gerard.lemson at gmail.com>
> <mailto:gerard.lemson at gmail.com
> <mailto:gerard.lemson at gmail.com>>> wrote:
>
> Hi
> What is meant by item 2, "An XML serialization
> of the DM".
> The standard representation (serialization?)
> of a VO-DML data
> model is VO-DML/XML, i.e. XML. And that is the
> representation
> that can be validated (step 1?) using
> automated means, for
> example using XSLT scripts in the vo-dml/xslt
> folder on volute at gavo.
> If 2) is meant to imply an XML serialization
> of an *instance* of
> the model, that we can only do once we have a
> standard XML
> representation of instances of models. That
> does not yet exist.
> The original VO-URP framework does contain an
> automated XML
> Schema generator for its version of VO-DML,
> that has not yet been
> ported to VO-DML.
> And of course the mapping document describes
> how one can describe
> instances serialized in VOTable, but that is a
> different standard.
>
> For what it's worthy, I think that an
> "implementation of VO-DML"
> is a data model expressed using that language
> (in VO-DML/XML to
> be precise) and validated using software. The
> latter enforces
> that the language should allow automated
> validtion.
> I think interoperable implementations of
> VO-DML are two or more
> valid models that are linked by "modelimport"
> relationships.
> I.e.one model "imports" the other(s) and uses
> types from the
> other as roles or super types in the
> definition of its own types.
> This is supported by the VODMLID/VODMLREF
> meachanism of the language.
>
> Cheers
> Gerard
>
>
> On Tue, May 10, 2016 at 9:04 AM, Matthew Graham
> <mjg at cd3.caltech.edu
> <mailto:mjg at cd3.caltech.edu>
> <mailto:mjg at cd3.caltech.edu
> <mailto:mjg at cd3.caltech.edu>>> wrote:
>
> Hi,
>
> We're trying to define specifically what
> would satisfy the
> reference implementation requirement for
> an IVOA Spec in the
> context of a data model. The proposal is that:
>
> (1) If the DM has been described using
> VO-DML it can be
> validated as valid VO-DML
>
> (2) An XML serialization of the DM can be
> validated
>
> so therefore is the combination of the two
> sufficient to
> demonstrate the validity and potential
> interoperability of
> the data model (which is the purpose of
> the reference
> implementations).
>
> Cheers,
>
> Matthew
>
>
>
>
>
> --
> Omar Laurino
> Smithsonian Astrophysical Observatory
> Harvard-Smithsonian Center for Astrophysics
> 100 Acorn Park Dr. R-377 MS-81
> 02140 Cambridge, MA
> (617) 495-7227 <tel:%28617%29%20495-7227>
>
>
>
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