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ready Astronomical Data Query Language

Abbreviation: ADQL

General Information
The Astronomical Data Query Language (ADQL) is the language used by the IVOA to represent astronomy queries posted to VO services. The IVOA has developed several standardized protocols to access astronomical data, e.g., Simple Image Access (SIA) protocol and Simple Spectral Access (SSA) protocol for image and spectral data respectively. These protocols might be satisfied using a single table query. However, different VO services have different needs in terms of query complexity and ADQL arises in this context. The ADQL specification makes no distinction between core and advanced or extended functionalities. Hence ADQL has been built according to a single Backus Naur Form (BNF) based language definition. Any service making use of ADQL would then define the level of compliancy to the language. This would allow the notion of core and extension to be service-driven and it would decouple the language from the service specifications. ADQL is based on the Structured Query Language (SQL), especially on SQL 92 1 2 3. . The VO has a number of tabular data sets and many of them are stored in relational databases, making SQL a convenient access means. A subset of the SQL grammar has been extended to support queries that are specific to astronomy. Similarly to SQL, the ADQL language definition is not semantically safe by design and therefore this specification defines syntactical correctness only. Type safety has been achieved as far as it can be done in SQL.


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Created in 2008

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How to cite this record ADQL; Astronomical Data Query Language; DOI:; Last edited: April 28, 2020, 1:55 p.m.; Last accessed: Jan 18 2022 7:02 a.m.

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Record added: March 20, 2018, 2:21 p.m.
Record updated: April 28, 2020, 1:54 p.m. by The FAIRsharing Team.

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IVOA Astronomical Data Query Language Version 2.00

Osuna, Pedro; Ortiz, Iñaki; Lusted, Jeff; Dowler, Pat; Szalay, Alexander; Shirasaki, Yuji; Nieto-Santisteban, Maria A.; Ohishi, Masatoshi; O'Mullane, William; VOQL-TEG Group; VOQL Working Group.
SAO/NASA Astrophysics Data System 2008

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Related Databases (1)
NASA/IPAC Extragalactic Database
NASA/IPAC Extragalactic Database (NED) is a comprehensive database of multiwavelength data for extragalactic objects, providing a systematic, ongoing fusion of information integrated from hundreds of large sky surveys and tens of thousands of research publications. The contents and services span the entire observed spectrum from gamma rays through radio frequencies. As new observations are published, they are cross- identified or statistically associated with previous data and integrated into a unified database to simplify queries and retrieval.

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