Wrapping up ADQL

[Pedro Osuna]

Dear all,

I have been quiet reading the different issues concerning our ADQL  
doc, nearly finished.

I would like to remind you that we should be in the period of  
answering the RFC comments, rather than introducing ourselves new  
functionalities (that ought to have been discussed before, within the  
TEG) or significative changes to the document.

Nevertheless, some small or agreed changes (during the Trieste  
meeting) are necessary, and therefore the following is my proposal to  
close the ADQL periple towards PR:

1.- We leave ELLIPSE out of this version of the document, and start  
thinking on whether it is well defined or not to eventually include it  
in a future version.
The fact that different well experienced people have different views  
on this very issue makes me skeptic on its easiness, and rather looks  
to me like the inclusion of the ELLIPSE function needs further  
thinking. The fact that we are issuing this version of the ADQL as PR  
does not mean that the ADQL will be frozen forever. We have agreed  
that this document will evolve in the future, and things might be  
added to it, but they will have to be discussed properly within the  
team and well researched and agreed.

2.- We adopt DEGREES (and square degrees) as units. This is a non- 
issue in my understanding, as conversions among them are trivial. It  
is just a matter of decision and agreement, and I believe we can all  
live with degrees, and will take the necessary steps to convert to  
whichever units we'd have our DB data in.

3.- We include BOX as per the latest inputs from Jeff. They have been  
agreed by Pat followed by Alex, so I give the latest definition as valid

4.- I have not understood the change of system_defined_function to  
geometry_function.  In my understanding system_defined_function is  
more general than geometry_function and could allocate other types of  
system defined functions to be included in the future if necessary  
that not necessarily would have to be geometry functions.
Therefore, unless there is a good reason against it, I call for not  
modifying the BNF on anything that has not been agreed, and leave it  
in this case as system_defined_function. This is not a criticism to  
Jeff's work, which is excellent and incredibly helpful for the ADQL  
doc, but just a reminder that we are only making changes in response  
to the RFC, and that we should refrain from introducing changes,  
despite how small, that could create more questions that the answers  
they provide with. As soon as the changes that reflect the comments  
from the RFC are included in the document (together with the  
agreements from the Trieste meeting), the document shall be ready for  
PR; thus, no changes other than the agreed ones should be put in.

So, to summarise, I call for your agreement or otherwise on the  
following plan:

- Remove ELLIPSe for this version
- Adopt DEGREES as units
- Include BOX as per agreement
- leave system_defined_function
- write agreed changes in the doc
- initiate auxiliary document with examples (not needed for the PR) -- 
 > Yuji and Benjamin --> discoped from this discussion

I will send _tomorrow_ a mail to the community saying that the RFC  
period is closed, then Inaki will edit the doc to include all the  
final issues, and once it is ready we'll distribute it to the TEG, and  
-if accepted- will pass it to the IVOA TCG for final examination.


That's all. Please send me you agreement (hopefully) or otherwise,  
with comments if any.

Thanks.
Cheers,
P.



_________________________________________
Pedro Osuna Alcalaya

European Space Agency (ESA)
European Space Astronomy Centre (ESAC)
Science Operations Department (SCI-O)
Science Archives and Computer Support Engineering Unit (SCI-OE)
e-mail: Pedro.Osuna at esa.int
Tel + 34 91 813 13 14    Fax: +34 91 813 11 72
_________________________________________
European Space Astronomy Centre (ESAC)
P.O. Box 78
E-28691 Villanueva de la Cañada
MADRID - SPAIN





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