DataLink inputParam PARAM/@value

crb at crb at
Thu Nov 16 10:20:55 CET 2017


My idea is that the VALUE attribute itself, if not empty, should be a  
default value for the parameter if nothing is supplied.

Besides that, there should/could be a VALUES element specifying (a)  
all the possible values for the parameter or (b) MIN/MAX values for  
the parameter.

I don't know if this VALUES element counts as having a VALUE from the  
votable standard point of view...


Quoting Mark Taylor <m.b.taylor at>:

[Hide Quoted Text]

I'm taking my first thorough look at DataLink with a view to writing
a client.  It mostly makes sense, but I have a question about the
use of the PARAM elements in the inputParams GROUP within a
service descriptor RESOURCE.

According to VOTable, PARAM elements must have a @value attribute.
But the @value doesn't seem to serve any purpose in an inputParams
GROUP, since the PARAM is just there to describe arguments that
are to be supplied, in some other way, to the described service.

Is the idea that (in both the ref-to-column and no-ref cases)
services must just fill in any syntactically legal value for the
@value attribute, and that clients should ignore that value altogether?
As far as I can see this is not mentioned in the DataLink document.
Can one of the authors or some other DataLink expert comment?

One other point: at the end of Section 4.3, it says

    'This PARAM would be added to the GROUP name="input" of the service

I think that should read 'name="inputParams"' - is that right?



Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at +44-117-9288776

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