VODataService becoming WD, then PR

[Roy Williams]

Pat
> An obvious example is that ADQL makes it possible to have columns of
> type "region" and return them in a select. The TAP spec will have to say that  
> the VOTable FIELD will be datatype="char" and arraysize-"*" and the content 
> will be encoded (STC/S encoding) as a string. I do not know off hand if the 
> FIELD allows one to say that the value is encoded; if not, then specs will 
> likely have to chose a single encoding. 
>   
I have been using UCD and UTYPE for this kind of recognition in the Vim 
application, the idea that some strings are treated specially. While 
making HTML presentation, for example, if there is a table column whose 
UCD is "meta.link.url", then it is rendered as a link <a href=...>, and 
if it is "meta.link.url;obs.image.jpeg", then it is rendered as an image 
<img src=...>. This works with other types of "special" strings that 
need interpretation, such as region defintions. I suppose it could all 
be rigorized with UTYPE at some point in the future.

> Anyway, having more richness of types in SQL is of little value when results 
> have to be converted to types allowed by VOTable.VOTable data types were copied from FITS binary table, so you can't blame the IVOA for this one! Anyway, richness cuts both ways. Its nice for the writer to output their quaternions however they like, but not so nice for the reader who has to parse and interpret everything!
>   

Roy

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California Institute of Technology
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