IVOA Query Language

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If you are interested in participating in the definition of a VO Query Language please contact Prof. Masatoshi Ohishi masatoshi.ohishi@nao.ac.jp.

We have a 3 layer model for VOQL as represented below.

ADQL-0.8.1

In the Boston 2005 meeting, the VOQL group agreed on the outline toward ADQL-0.8.1 (see below), and the working document was published.

• Specification - ADQL-0.8.1.pdf
• Just the schema - ADQL-0.8.xsd

It should be noted that it is a working document toward an IVOA standard VOQL specification version 1. The content of the document will be used for the January 2005 demos. The document was created based on the Boston 2004 agreement, however, several new features, such as CREATE,INSERT,UPDATE,DELETE, have not yet been included because these will actually create a huge increase in the size of the grammar. The ad hoc group is working in the backyard to include these features, and an improved working document, ADQL-0.8.2, is expected to appear very soon. SkyNodeInterface specification will also be modified accordingly.

The process of generating the ADQL schema are described in ADQL Schema generation steps.

An example XSL style sheet for converting ADQL/x to ADQL/s (strings) has been provided by NCSA adql2sql-ns.xsl.

Further information and some tools may be found at http://skydev.pha.jhu.edu/develop/vo/adql/

A java client for the translation service has been prepared.

Enhancements due for ADQL0.8.1

• Functions : Built-in funtion support in ADQL
• DML : Insert, Delete, Update (Create, Drop ?)
• Comments : SQL style comments should be in ADQL
• Sub Queries: Currently this is not suported
• INTO : MyDb, MySpace for both select and insert
• Top : tie down semantics
• GCDIST : This is just another function .
• XMATCH : Move sigma inside the bracket (or drop it ?) Add + for outer join and ? for uncovered areas
• JOIN : Use Explicit JOIN syntax
• UNITS : Add to ADQL/s, ADQL/x (need more metadata on table in SkyNode)
• XPATH : Allow XPath like column names

SkyNode

SkyNodes and the SkyNode portal would form layer 2 and 1 of this system. At the Strasbourg meeting the skynode spec was split in two. Since release of the Standard Interfaces this has also been reomved from skynode. Finally the portal section has also been reomved leaving a leaner Skynode document.

• SkyNodeInterface-0.7.4.pdf

Latest SkyNode WSDL from http://openskyquery.net/nodes/sdss/nodeb.asmx?wsdl

Ther eare currently Java and .NET implementations of this. Nodes are registered in the Registry and may be intereacted with through the OpenSkyQuery Portal

Comments should be posted on the VOQL mailing list as specified below.

VOQL Sessions in Pune 2004 October

• Draft Agenda for October, 2004

WG Roadmap

• May 2004 version 0.7.4
• May 24-28, 2004 Interop meeting
• Work to include Units, XMATCH – Ad Hoc Group (Wil O'Mullane, Clive Page, Martin Hill, Yuji Shirasaki, Sébastien Derrière and the chair). See the details above. Need to describe semantics of ADQL more clearly
• Submit ADQL-0.8 in July
• Sep 2004 Interop meeting Agreement --> ADQL 0.9 & interaction between us and Registry/DAL/DM groups. After interaction with Registry/DAL/DM groups and discussion within our group, we prepare a draft for ADQL 1.0. When it has been approved by the IVOA executive committee, it will become ADQL 1.0.
• Sep/Oct (?) 2004 GGF12 @ Brussels : to report activities of the VO community
• Work toward January Demos
• Jan 2005 Demos by ADQL-1.0 & SkyNode-1.0
• Improvements including New data types proposed by Yuji SHirasaki
• May 2005 Interop meeting / GGF joint WS in Japan

Discussion on ADQL-1.x, SkyNode-1.x ?

Mailing-list

• General working-group discussion archive.

Related Links

• Sky Query - About the cross match

References

• Budavári, T., et al. 2002, ADASS XII, O10-1
• Malik, T., et al. 2002, CIDR `03, p.17, "SkyQuery: A Web Service Approach to Federate Databases"
• Budavári, T., et al. 2003, ADASS XIII, P2-18

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• ADQL-0.8.1.pdf: A Working Document for ADQL-0.8.1

• DraftAgenda_VOQL_Oct04.pdf: Preliminary Agenda Items for the Pune meeting