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<tt>Hello DAL,<br>
<br>
Here is a little status report about the ADQL-2.1 document.<br>
<br>
We already have some open issues/Pull-Requests that would need a
review.<br>
If some of the following topics interest you, do not hesitate to
take a<br>
look on the corresponding Issue/PR description and discussion.<br>
</tt><tt><br>
</tt><b><tt> * Open issues:</tt></b><tt><br>
</tt><tt> </tt><tt><br>
</tt><tt> - <a moz-do-not-send="true"
href="https://github.com/ivoa-std/ADQL/issues/32">Boolean</a></tt><tt><br>
</tt><tt> - <a moz-do-not-send="true"
href="https://github.com/ivoa-std/ADQL/issues/16">UDF-catalogue</a></tt><tt><br>
</tt><tt> - <a moz-do-not-send="true"
href="https://github.com/ivoa-std/ADQL/issues/29">Geometries fix</a></tt><tt><br>
</tt><tt> - <a moz-do-not-send="true"
href="https://github.com/ivoa-std/ADQL/issues/10">Coordinate
system specification</a></tt><tt><br>
</tt><tt> </tt><tt><br>
</tt><b><tt> * Pull Requests under review:</tt></b><tt><br>
</tt><tt> </tt><tt><br>
</tt><tt> - <a moz-do-not-send="true"
href="https://github.com/ivoa-std/ADQL/pull/26">UDF-catalogue</a></tt><tt><br>
</tt><tt> - <a moz-do-not-send="true"
href="https://github.com/ivoa-std/ADQL/pull/41">Geometries fix</a></tt><tt><br>
</tt><tt> </tt><tt><br>
</tt><b><tt> * Brief summaries:</tt></b><tt><br>
</tt><tt> </tt><tt><br>
</tt><tt> <b>- Boolean:</b><br>
It has been proposed to add the boolean values `True` and
`False` and to<br>
allow boolean comparison with resp. 1/0 and True/False. It
would also be<br>
possible to write boolean expressions as such without a
comparison.<br>
Considering the non-homogeneous aspect of existing DBMS
regarding the<br>
boolean values/datatype and the complexity raise of the
grammar if we want<br>
to support it, the current decision is to postpone `boolean`
for a later<br>
version of ADQL</tt><tt><br>
</tt><tt> </tt><tt><br>
</tt><tt> <i><b>=> Go see the discussion for the other
proposed alternatives.</b></i></tt><i><b><tt><br>
</tt></b></i><i><b><tt> In absence of answer, ADQL-2.1
will not include any boolean for now.</tt></b></i><tt><br>
</tt><tt> </tt><tt><br>
</tt><tt> <b>- UDF-catalogue:</b><br>
An Endorsed Note gathering the definitions of frequently used
User Defined<br>
Functions. The idea is that everybody uses the same
definition, for the<br>
sake of our users. This EN should be soon accepted.</tt><tt><br>
</tt><tt> </tt><tt><br>
</tt><tt> <i><b>=> At that moment, the corresponding Issue
and Pull-Request will be</b></i></tt><i><b><tt><br>
</tt></b></i><i><b><tt> completed in ivoa-std/ADQL. No
input required for this topic.</tt></b></i><tt><br>
</tt><tt> </tt><tt><br>
</tt><tt> <b>- Geometries Fix:</b><br>
This fix aims to fix a syntax ambiguous situation with
`POLYGON` due to the<br>
first argument (coordinate system) becoming optional. This
has finally been<br>
fixed by a new Erratum about the datatype of the coordinate
system<br>
argument.</tt><tt><br>
</tt><tt> </tt><tt><br>
</tt><tt> <i><b>=> The corresponding Pull-Request is waiting
for someone to review/accept</b></i></tt><i><b><tt><br>
</tt></b></i><i><b><tt> it. After that, it and its
corresponding Issue can be closed.</tt></b></i><tt><br>
</tt><tt> </tt><tt><br>
</tt><tt> <b>- Coordinate system specification:</b><br>
With ADQL-2.1, the coordinate system argument of geometries
like `POINT`,<br>
`CIRCLE`, ... become deprecated and so, it is optional. In a
later version,<br>
it will be removed. It means that it is no longer possible to
explicitly<br>
specify the input coordinate system of geometries. The
consequence is that<br>
coordinate system convertion is not explicitely possible any
more while<br>
trying to match geometries each other (e.g. with `CONTAINS`,
`INTERSECTS`)<br>
(note that nothing prevents the ADQL service to perform it
automatically<br>
with an internal mechanism). This is a feature actually
supported by very<br>
few TAP services but is however very important for services
offering<br>
positions at different coordinate systems (e.g. GAVO,
VizieR). The proposed<br>
solution is to rely on UDF-Catalogue. GAVO has already
defined some UDFs<br>
which are listed in this PEN, but with the prefix `gavo_`.
When other TAP<br>
services will need such functions, there should be
discussions all together<br>
to converge toward a common UDF definition ; once done, these
functions<br>
will be prefixed with `ivo_`.</tt><tt><br>
</tt><tt> </tt><tt><br>
</tt><tt> <i><b>=> I propose to close this issue unless
there are other reactions.</b></i></tt><tt><br>
<br>
</tt><br>
<tt><b> * Remaining issues:</b><br>
<br>
- <a moz-do-not-send="true"
href="https://github.com/ivoa-std/ADQL/issues/20">Fix set
operators</a><br>
- <a moz-do-not-send="true"
href="https://github.com/ivoa-std/ADQL/issues/11">TIMESTAMP vs
CAST</a><br>
<br>
<br>
Do not hesitate to react</tt><tt> in the discussions</tt><tt> on
GitHub, or otherwise by email.<br>
<br>
Cheers,<br>
Grégory M.<br>
<br>
</tt><tt></tt>
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