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<p style="margin-bottom: 0in">Concerning the usage of quotes around
the VizieR funny names:<br>
<br>
<br>
Curenly TAPVizieR provides a XML
output (see url
<a class="moz-txt-link-freetext" href="http://tapvizier.u-strasbg.fr/TAPVizieR/tap/tables">http://tapvizier.u-strasbg.fr/TAPVizieR/tap/tables</a>)
without quotes but completed with the schema (ex:
table_name=vizls.II/246/out).<br>
The main difficulties for clients to
work with TAPVizieR are the VizieR "funny names" (tables,
columns in VizieR contains special characters like "/", "."
, ...)<br>
<br>
Dave Morris suggested translation function as: (i'm
sceptical with this kind of function which are not
user-friendly)<br>
select * from translate("II/246/out")<br>
<br>
Mark
Taylor talked about some ambiguities when column, tables contains
some "." (ex: vizb.B/avo.rad/catalog) because it is
difficult/impossible to separate the shema_name and the
table_name.<br>
TAPVizieR could provide the XML TAP schema with quotes
(as suggested by M.Taylor).<br>
This is may be not an ideal solution,
but it is a solution for this ambiguity and it could simplify the
clients implementation when they have to work with the VizieR
funny
names.. <br>
If we choose this way, to have an explicit specification
(as proposed by Mark Taylor) in the TAP documentation would be
appreciated.<br>
<br>
However, this ambiguity could be avoided with
removing the schema name of the table_name (my implementation
which
concatenate the schema_name and the table_name was not a good
idea).<br>
The XML tapschema describes the schema in a XML node
containing the schema name and the tables of the schema. So it is
not
needed to give the schema name again in the
table_name.<br>
<br>
<schema><br>
<name>viz4</name><br>
....<br>
<table type="base_table"><br>
<name>B/avo.rad/catalog</name><br>
....<br>
</table><br>
....<br>
</schema><br>
<br>
Note: the subdivision in VizieR
(viz2,viz3,vizA,...) is not very clear and is the result of
technicals subdivision without any logic for astronomers..(i could
update that..)<br>
<br>
In any case, i would like to improve the
TAPVizieR service and so, i am open to any proposals.<br>
<br>
Gilles Landais</p>
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<div class="moz-cite-prefix">On 27/04/2015 17:57,
<a class="moz-txt-link-abbreviated" href="mailto:dal-request@ivoa.net">dal-request@ivoa.net</a> wrote:<br>
</div>
<blockquote cite="mid:mailman.466.1430150232.1199.dal@ivoa.net"
type="cite">
<pre wrap="">Send dal mailing list submissions to
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When replying, please edit your Subject line so it is more specific
than "Re: Contents of dal digest..."
Today's Topics:
1. Re: What does TOP mean ? (Arnold Rots)
2. table_name syntax (Mark Taylor)
3. Re: What does TOP mean ? (Walter Landry)
4. Re: What does TOP mean ? (Markus Demleitner)
5. Re: What does TOP mean ? (Arnold Rots)
6. Re: What does TOP mean ? (Douglas Tody)
----------------------------------------------------------------------
Message: 1
Date: Mon, 27 Apr 2015 09:43:46 -0400
From: Arnold Rots <a class="moz-txt-link-rfc2396E" href="mailto:arots@cfa.harvard.edu"><arots@cfa.harvard.edu></a>
To: DAL mailing list <a class="moz-txt-link-rfc2396E" href="mailto:dal@ivoa.net"><dal@ivoa.net></a>
Subject: Re: What does TOP mean ?
Message-ID:
<a class="moz-txt-link-rfc2396E" href="mailto:CAJXToE_roWrKwCDyC9cBgQxcdThLrUvoQkqvikhp2wC5B9sU6A@mail.gmail.com"><CAJXToE_roWrKwCDyC9cBgQxcdThLrUvoQkqvikhp2wC5B9sU6A@mail.gmail.com></a>
Content-Type: text/plain; charset="utf-8"
Yes, you need an observatory-specific model to calculate a score.
By its very nature, therefore, it will only be a relative score.
Example:
For Chandra we implemented a score that is based on instrument, exposure
time, and off-axis angle
(PSF degrades with increasing off-axis angle).
- Arnold
-------------------------------------------------------------------------------------------------------------
Arnold H. Rots Chandra X-ray
Science Center
Smithsonian Astrophysical Observatory tel: +1 617 496
7701
60 Garden Street, MS 67 fax: +1 617
495 7356
Cambridge, MA 02138
<a class="moz-txt-link-abbreviated" href="mailto:arots@cfa.harvard.edu">arots@cfa.harvard.edu</a>
USA
<a class="moz-txt-link-freetext" href="http://hea-www.harvard.edu/~arots/">http://hea-www.harvard.edu/~arots/</a>
--------------------------------------------------------------------------------------------------------------
On Mon, Apr 27, 2015 at 3:25 AM, Markus Demleitner <
<a class="moz-txt-link-abbreviated" href="mailto:msdemlei@ari.uni-heidelberg.de">msdemlei@ari.uni-heidelberg.de</a>> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi Petr, hi SSA crowd,
On Sat, Apr 25, 2015 at 01:38:26AM +0200, Petr Skoda wrote:
</pre>
<blockquote type="cite">
<pre wrap="">
And does anybody implemented TOP in scoring manner in SSAP ?
</pre>
</blockquote>
<pre wrap="">
Well, DaCHS accepts TOP but treats it equivalently to MAXREC so far
(which I claim is legal, as that simply means I give all matching
results the same score).
The basic difficulty in doing a meaningful implementation is that you
need to compute a score, and this kind of scoring in general is
either difficult (because to do it properly you need a statistical
model of both the data and the user) or haphazard (involving
combining more or less ad-hoc measures for how good a match is for a
certain constraint weighted... somehow).
I think it would be a moderately worthwhile effort to create a model
of either kind for SSAP's parameter set and validate it with user
studies. Has anyone perhaps already started on such a thing?
My suspicion is that this model could work well across a multitude of
services and domains with no or just a single parameter. Be that as
it may, I'm afraid I don't see GAVO tackling something like that any
time soon.
Cheers,
Markus
</pre>
</blockquote>
<pre wrap="">-------------- next part --------------
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------------------------------
Message: 2
Date: Mon, 27 Apr 2015 15:00:31 +0100 (BST)
From: Mark Taylor <a class="moz-txt-link-rfc2396E" href="mailto:m.b.taylor@bristol.ac.uk"><m.b.taylor@bristol.ac.uk></a>
To: <a class="moz-txt-link-abbreviated" href="mailto:dal@ivoa.net">dal@ivoa.net</a>
Subject: table_name syntax
Message-ID:
<a class="moz-txt-link-rfc2396E" href="mailto:alpine.LRH.2.11.1504271454250.9069@andromeda.star.bris.ac.uk"><alpine.LRH.2.11.1504271454250.9069@andromeda.star.bris.ac.uk></a>
Content-Type: TEXT/PLAIN; charset=US-ASCII
Hi DAL,
I have an arcane query about how to represent and interpret TAP
service table names that appear in
(a) the table_name column of the TAP_SCHEMA.tables table
(b) tableset/schema/table/name elements in a TableSet document
(I'm assuming the answer is the same for both unless somebody says
different)
TAP v1.0 sec 2.6.2 says:
The value of the table_name should be the string that is
recommended for use in querying the table; it may or may not be
qualified by schema and catalog name(s) depending on the implementation
requirements. The fully qualified table name is defined by the
ADQL language and follows the pattern [[catalog.]schema.]table.
My question is: if the catalog, schema or table parts of the table_name
do not match ADQL's identifier syntax, must they be quoted as delimited
identifiers?
For many TAP services this is probably not an issue, but it sure is
for TAPVizieR, where table names usually contain the "/" character
and sometimes other non-identifier characters too. For instance,
(<a class="moz-txt-link-freetext" href="http://tapvizier.u-strasbg.fr/beta/TAPVizieR/tap">http://tapvizier.u-strasbg.fr/beta/TAPVizieR/tap</a>):
select top 3 schema_name, table_name from tap_schema.tables
where schema_name='viz4'
gives
+-------------+-------------------+
| schema_name | table_name |
+-------------+-------------------+
| viz4 | B/avo.rad/catalog |
| viz4 | B/avo.rad/wsrt |
| viz4 | B/bax/bax |
+-------------+-------------------+
Should it instead give
+-------------+---------------------+
| schema_name | table_name |
+-------------+---------------------+
| viz4 | "B/avo.rad/catalog" |
| viz4 | "B/avo.rad/wsrt" |
| viz4 | "B/bax/bax" |
+-------------+---------------------+
?
I initially thought the answer to this was no.
But if that's the case, how do I tell[*] whether the
first entry in the result above is
table "B/avo.rad/catalog" from an unnamed schema (which it is) or
table "rad/catalog" from schema "B/avo" (which it's not).
If the answer is yes, then (a) TAPVizier and possibly some other
services will need to change their content to comply, and
(b) what is the rule for other TAP_SCHEMA columns like
schema_name and column_name (and others?)? Quoting these columns
would be unnecessary (since there is no possibility of delimited
parts in this case), but it would seem inconsistent to require
quoting for some of these metadata columns and not others;
at least it should be documented explicitly.
Thanks!
Mark
[*] the ugly hack answer is obviously: see if the apparent schema
is the same as the schema_name column. This would give you an
almost-certainly-correct indication of what you're looking at,
but it's fiddly, inelegant and not bulletproof.
--
Mark Taylor Astronomical Programmer Physics, Bristol University, UK
<a class="moz-txt-link-abbreviated" href="mailto:m.b.taylor@bris.ac.uk">m.b.taylor@bris.ac.uk</a> +44-117-9288776 <a class="moz-txt-link-freetext" href="http://www.star.bris.ac.uk/~mbt/">http://www.star.bris.ac.uk/~mbt/</a>
------------------------------
Message: 3
Date: Mon, 27 Apr 2015 07:29:08 -0700 (PDT)
From: Walter Landry <a class="moz-txt-link-rfc2396E" href="mailto:wlandry@caltech.edu"><wlandry@caltech.edu></a>
To: <a class="moz-txt-link-abbreviated" href="mailto:dal@ivoa.net">dal@ivoa.net</a>
Subject: Re: What does TOP mean ?
Message-ID: <a class="moz-txt-link-rfc2396E" href="mailto:20150427.072908.190108314094379184.wlandry@caltech.edu"><20150427.072908.190108314094379184.wlandry@caltech.edu></a>
Content-Type: Text/Plain; charset=us-ascii
Markus Demleitner <a class="moz-txt-link-rfc2396E" href="mailto:msdemlei@ari.uni-heidelberg.de"><msdemlei@ari.uni-heidelberg.de></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi Petr, hi SSA crowd,
On Sat, Apr 25, 2015 at 01:38:26AM +0200, Petr Skoda wrote:
</pre>
<blockquote type="cite">
<pre wrap="">
And does anybody implemented TOP in scoring manner in SSAP ?
</pre>
</blockquote>
<pre wrap="">
Well, DaCHS accepts TOP but treats it equivalently to MAXREC so far
(which I claim is legal, as that simply means I give all matching
results the same score).
</pre>
</blockquote>
<pre wrap="">
I thought that the difference between MAXREC and TOP is that MAXREC
requires an overflow indicator, while TOP would prohibit it.
Otherwise, I agree. We also treat them the same.
Cheers,
Walter Landry
------------------------------
Message: 4
Date: Mon, 27 Apr 2015 17:03:14 +0200
From: Markus Demleitner <a class="moz-txt-link-rfc2396E" href="mailto:msdemlei@ari.uni-heidelberg.de"><msdemlei@ari.uni-heidelberg.de></a>
To: <a class="moz-txt-link-abbreviated" href="mailto:dal@ivoa.net">dal@ivoa.net</a>
Subject: Re: What does TOP mean ?
Message-ID: <a class="moz-txt-link-rfc2396E" href="mailto:20150427150314.GA23328@ari.uni-heidelberg.de"><20150427150314.GA23328@ari.uni-heidelberg.de></a>
Content-Type: text/plain; charset=utf-8
Hi Arnold,
On Mon, Apr 27, 2015 at 09:43:46AM -0400, Arnold Rots wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Yes, you need an observatory-specific model to calculate a score.
By its very nature, therefore, it will only be a relative score.
Example:
For Chandra we implemented a score that is based on instrument, exposure
time, and off-axis angle
(PSF degrades with increasing off-axis angle).
</pre>
</blockquote>
<pre wrap="">
Well, yes, that could be part of it, but the way I understand
things --
[...] the general idea is that the better a candidate dataset
matches the query, the higher the score it receives. (1.1, P.27)
-- TOP's intended function is essentially like Google's ranking: it
gives "how well" a given returned row matches a data set. Hence, for
a given dataset score would be different for different queries, and
while a global quality measure might play a role, it certainly
wouldn't be expected to dominate the response. Or am I completely
off here?
And regarding Walter's interjection:
</pre>
<blockquote type="cite">
<pre wrap="">I thought that the difference between MAXREC and TOP is that MAXREC
requires an overflow indicator, while TOP would prohibit it.
</pre>
</blockquote>
<pre wrap="">
Interesting thought -- is it intended to work this way? [it doesn't
in DaCHS, and a quick search in the 1.1 specs didn't give me anything
pointing in that direction]
Cheers,
Markus
------------------------------
Message: 5
Date: Mon, 27 Apr 2015 11:37:48 -0400
From: Arnold Rots <a class="moz-txt-link-rfc2396E" href="mailto:arots@cfa.harvard.edu"><arots@cfa.harvard.edu></a>
To: DAL mailing list <a class="moz-txt-link-rfc2396E" href="mailto:dal@ivoa.net"><dal@ivoa.net></a>
Subject: Re: What does TOP mean ?
Message-ID:
<a class="moz-txt-link-rfc2396E" href="mailto:CAJXToE-fKk5XcUe94LmyDu37vFf0fo3-WotqdtEfpz-vy01PQg@mail.gmail.com"><CAJXToE-fKk5XcUe94LmyDu37vFf0fo3-WotqdtEfpz-vy01PQg@mail.gmail.com></a>
Content-Type: text/plain; charset="utf-8"
No, it's not global, but applied to the datasets that satisfy the query.
Though instrument and exposure time do not change, the off-axis
parameter does. In the case of a cone search, for instance, it is
the angle between the center of the cone and the direction of the
optical axis.
- Arnold
-------------------------------------------------------------------------------------------------------------
Arnold H. Rots Chandra X-ray
Science Center
Smithsonian Astrophysical Observatory tel: +1 617 496
7701
60 Garden Street, MS 67 fax: +1 617
495 7356
Cambridge, MA 02138
<a class="moz-txt-link-abbreviated" href="mailto:arots@cfa.harvard.edu">arots@cfa.harvard.edu</a>
USA
<a class="moz-txt-link-freetext" href="http://hea-www.harvard.edu/~arots/">http://hea-www.harvard.edu/~arots/</a>
--------------------------------------------------------------------------------------------------------------
On Mon, Apr 27, 2015 at 11:03 AM, Markus Demleitner <
<a class="moz-txt-link-abbreviated" href="mailto:msdemlei@ari.uni-heidelberg.de">msdemlei@ari.uni-heidelberg.de</a>> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi Arnold,
On Mon, Apr 27, 2015 at 09:43:46AM -0400, Arnold Rots wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Yes, you need an observatory-specific model to calculate a score.
By its very nature, therefore, it will only be a relative score.
Example:
For Chandra we implemented a score that is based on instrument, exposure
time, and off-axis angle
(PSF degrades with increasing off-axis angle).
</pre>
</blockquote>
<pre wrap="">
Well, yes, that could be part of it, but the way I understand
things --
[...] the general idea is that the better a candidate dataset
matches the query, the higher the score it receives. (1.1, P.27)
-- TOP's intended function is essentially like Google's ranking: it
gives "how well" a given returned row matches a data set. Hence, for
a given dataset score would be different for different queries, and
while a global quality measure might play a role, it certainly
wouldn't be expected to dominate the response. Or am I completely
off here?
And regarding Walter's interjection:
</pre>
<blockquote type="cite">
<pre wrap="">I thought that the difference between MAXREC and TOP is that MAXREC
requires an overflow indicator, while TOP would prohibit it.
</pre>
</blockquote>
<pre wrap="">
Interesting thought -- is it intended to work this way? [it doesn't
in DaCHS, and a quick search in the 1.1 specs didn't give me anything
pointing in that direction]
Cheers,
Markus
</pre>
</blockquote>
<pre wrap="">-------------- next part --------------
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------------------------------
Message: 6
Date: Mon, 27 Apr 2015 09:56:50 -0600 (MDT)
From: Douglas Tody <a class="moz-txt-link-rfc2396E" href="mailto:dtody@nrao.edu"><dtody@nrao.edu></a>
To: Markus Demleitner <a class="moz-txt-link-rfc2396E" href="mailto:msdemlei@ari.uni-heidelberg.de"><msdemlei@ari.uni-heidelberg.de></a>
Cc: DAL mailing list <a class="moz-txt-link-rfc2396E" href="mailto:dal@ivoa.net"><dal@ivoa.net></a>
Subject: Re: What does TOP mean ?
Message-ID: <a class="moz-txt-link-rfc2396E" href="mailto:alpine.OSX.1.00.1504270948250.517@colorado2.tuc.noao.edu"><alpine.OSX.1.00.1504270948250.517@colorado2.tuc.noao.edu></a>
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
The algorithm used to compute the score for a dataset is up to the
data center and service, but can include both a best-match term and a
quality term (clearly best-match would be more important for an
individual query).
The main difference between MAXREC and TOP is scoring and sort by score.
Usually if TOP is specified MAXREC would not matter as it is likely to
be much larger, but MAXREC if specified should still be in effect and
could result in an overflow indication.
A service could treat TOP the same as MAXREC (all records having the
same score), however computing a useful scoring would be preferable.
Finally, Google made billions developing just such an algorithm! It is
what made their search service stand out from the others, in the early
days.
- Doug
On Mon, 27 Apr 2015, Markus Demleitner wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi Arnold,
On Mon, Apr 27, 2015 at 09:43:46AM -0400, Arnold Rots wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Yes, you need an observatory-specific model to calculate a score.
By its very nature, therefore, it will only be a relative score.
Example:
For Chandra we implemented a score that is based on instrument, exposure
time, and off-axis angle
(PSF degrades with increasing off-axis angle).
</pre>
</blockquote>
<pre wrap="">
Well, yes, that could be part of it, but the way I understand
things --
[...] the general idea is that the better a candidate dataset
matches the query, the higher the score it receives. (1.1, P.27)
-- TOP's intended function is essentially like Google's ranking: it
gives "how well" a given returned row matches a data set. Hence, for
a given dataset score would be different for different queries, and
while a global quality measure might play a role, it certainly
wouldn't be expected to dominate the response. Or am I completely
off here?
And regarding Walter's interjection:
</pre>
<blockquote type="cite">
<pre wrap="">I thought that the difference between MAXREC and TOP is that MAXREC
requires an overflow indicator, while TOP would prohibit it.
</pre>
</blockquote>
<pre wrap="">
Interesting thought -- is it intended to work this way? [it doesn't
in DaCHS, and a quick search in the 1.1 specs didn't give me anything
pointing in that direction]
Cheers,
Markus
</pre>
</blockquote>
<pre wrap="">
------------------------------
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End of dal Digest, Vol 67, Issue 10
***********************************
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