[fitsbits] Start of the 'INHERIT' Public Comment Period

[Doug Tody]

On Sat, 7 Apr 2007, Steve Allen wrote:

> On Fri 2007-04-06T14:52:27 +0000, Archie Warnock hath writ:
>> No, but avoiding potential errors by not duplicating text strings is a
>> worthy effort, as we learned long ago from relational database theory.

I mentioned this point in my earlier mail as well.  Within IRAF, the
main motivation for INHERIT was to avoid duplication of information
in multiple places within a MEF.  This would very likely lead to
problems with updates.  It could also have advantages when viewing a
MEF as a more complex object.

> What FITS did not learn from relational database theory was how to
> create mechanisms which document and enforce the self consistency of
> data which have been neatly separated into distinct logical chunks.
>
> I think that's the way forward.

One could also say that this is not a FITS issue at all, but rather a
more general data modeling issue.  We are already getting into this
within VO in several different contexts.  What we will probably be
doing is mapping some more general model or mechanism into a FITS
representation.  Typically such relationships and models need to be
consistent regardless of how the information is stored, with FITS being
only part of the picture.  While this can be done with the current
FITS mechanisms, it is awkward.  The sometimes discussed "FITS 2.0",
if it ever comes to pass, could address the respresentation issues
but should not change the basic FITS data models.

 	- Doug