action items

[Rob Seaman]

Matthew Graham wrote:

> Given that VOEvent 1.1 has no data typing and there is a requirement  
> to support range queries in SEAP (e.g. 16 < mag1 < 20), how do we  
> overcome the mismatch? I can see three (not mutually exclusive)  
> alternatives:
>
> (1) Rely on implementor knowledge: The SEAP server 'knows' that mag1  
> takes numerical values and so will parse and convert any range  
> queries appropriately. At the worst it can construct a standard SQL  
> string to send against the DB, catch the error when this fails  
> because of data type mismatch and return a HTTP 500.
>
> (2) Information about the data dictionary that the VOEvent stream  
> uses in its <What> section is registered in a registry. This  
> includes details about the data type and so the SEAP service can  
> poll the registry to do its data type checking.
>
> (3) SEAP is only defined to run against VOEvent 2.0 where we have  
> data type information (maybe).

#1 is what we have now.  It is not sufficient.  #3 is desirable,  
perhaps necessary, but also insufficient - whatever the protocol  
allows, we are unlikely to win consensus to force data types be  
present for conformance.  Thirty years in, FITS headers are still  
seeing numerical keywords expressed as strings.  It simply can't be  
illegal to say "19" as a string.

Rather, I think SEAP is a good tool to drive forward improvements to  
VOEvent's ties to the registry.  Either we use XML schema (or whatever  
comes after the current flawed schema) in all their gory detail, or we  
have to provide some alternate mechanism for distributing knowledge of  
the semantics of different authors/publishers' use of params.  If not  
the registry, then what?

We should discuss the best way to drive VOEvent v2.0, SEAP and  
registry-based VOEventStreams forward.  If they are tied together,  
which has to happen first?  Who will commit to deploying  
infrastructure conformant to all three?  Etc.  I don't believe it is  
any more trouble to wrap this all up with a pretty bow, we simply have  
to lay out the steps to get there.

Rob