Time Series Cube DM - IVOA Note

[Markus Demleitner]

Hi Mark,

On Tue, Feb 21, 2017 at 01:18:07PM -0500, CresitelloDittmar, Mark wrote:
> I think this version connection is the only point to be concerned about.
>   + if a Datatset-2.0 came out, you could annotate your file with both
> Dataset-1.x and 2.0 annotation,
>      (I think... that is a question for the Mapping folks)

That's been a requirement from the early days of the utypes tiger
team, and all mapping plans I'm aware of at the moment support this.

>   + But, in validating the instance, the version which is associated with
> the model would
>      be the one used (Dataset-1.x).  The 2.0 content would not be
> 'official/valid' until the model migrated
>      to be based off the new version.

Well, you're always validating *against* something -- for instance,
something can be valid XML (e.g., against some DTD or the VOResource
schema), and yet invalid VOTable.  So, a document can be valid or
invalid Dataset-1.0 and/or valid or invalid Dataset-2.4
independently.

Now, my appeal is to have the same property across DMs: We should
build things so that a document can be valid NDCube-1.0 regardless of
whether it uses Dataset-1.0 or Dataset-2.4 or both, or even none
of them.  The point of my previous mail was that that's feasible; at
least for STC (which is what I've spent most thoughts on) I'm pretty
sure that whereever the different DMs need to "share" information,
this can be effected though coreference to columns and params.

    -- Markus