1. Progress Report of VOQL WG
May 15 (Thu)
Masatoshi Ohishi (Japan)

2. 1. WG on 14th About 20 people attended the WG:
UK, US, Canada, Germany, France, ESA, Korea, Japan
Secretary: Bob Mann
minutes – on TWiKi
8 presentations
Succeeded to establish a human-network (layer 8) for our common goal.

3. 2. Activities on QLs 2 major trends Extended SQL based QL
XML-based query

4. Extended SQL based QL More than 90 % of astronomical DBs are
RDBs, and SQL is used to query to DBs.
Functions are not sufficient to make
access to federated DBs (e.g., multi-
wavelength) with astronomical specific
requests.
Prototypes are running.
Compact, and easy to learn.

5. EX. JVO QL
Retrieves catalog data and images from multiple data servers via a single user interface
Extension of SQL
Catalog.UCD
Box(Point(c1.ra,c1.dec), width1,height1)
XMATCH(c1,c2,!c3,…)< 3 arcsec
Select Catalog: Keyword1 & Keyword2
Select by [[MAX|MIN](PROPERTY) | ALL] [NAME]
Area : [inside|outside] area0
Area1 [overlap|union] area2 | shape
SHAPE: box, circle, oval, triangle,point
DIFF(x.obs_date, y.obs_date) > 30 days

6. XML-based QLs
Possible to make semantic expressions, but a QL file becomes larger than SQL-based QLs.
More generalized than SQL-based QLs.
It will take at least two years to finalize the basic delevopments.
XMLs are rapidly developling.

7. EX. Problem Statement Language
Return RA, Dec, Vmag for stars with 13<Vmag<15 and 10:12:53.5<RA<13:13:43 and 18:38:00<DE< 18:40:00.
PSL:
<object class=“star”>
<property name=“Vmag”>
<range min=“13” max=“15”/>
<value>?vmag</value>
</property>
<property name=“RA”>
<range min=“10:12:53.5” max=“13:13:43”/>\
<value>?ra</value>
<property name=“DE”>
<range min=“18:38:00” max=“18:40:00”/>
<value>?de</value>
</object>

8. Agreement Two level approach
Level-1 : Extended SQL-based QL as the first version, we develop a prototype by the end of 2003, and will revise by the end of 2004.(Wil O’Mullane and Naoki Yasuda)
Level-2 : Higher-level VOQL will be based on the XML-based QLs. Need to watch progress on XML-based QLs. (Ed Shaya and Patrick Dowler)

9. 3. Science Use Cases
It is important to collect science use cases to consider which functions are necessary to be implemented in the VOQL.
XMATCH, LINEMATCH, ,,,,

10. 4. Definition of VOQL ? What is the definition of VOQL ??
Option A) VOQL expresses only what astronomers want to “OBSERVE” on VO(s).
science cases →(VOQL)→ VO system
Option B) VOQL is a protocol just to communicate between two VOs.
Option C) VOQL is a general protocol to communicate inside VO system(s).

11. Possible Definition needs info on data model !!
"A language for the exchange of astronomers' queries with the VO system,
which allows expression of the science user scenarios, within reason, and
output structured data.
needs info on data model !!

12. 5. Requirements for VOQL
Need to express scientific use cases to the maximum extent (not ALL !)
Extensible
Easy to learn (For averaged users GUIs are necessary. Advanced people may want to describe/ edit requests.)
Independent from metadata / registry

13. Further Discussion
Continued on the net :
Join us !!