IVOA Data Access Layer



The task of the DAL working group is to define and formulate VO standards for remote data access. Client data analysis software will use these services to access data via the VO framework; data providers will implement these services to publish data to the VO. The DAL working group will define the scope of the DAL standards, outline a process by which DAL standards are defined, and generate the initial version 1.0 of the DAL standard. This standard will provide guidance to data centers and survey projects when designing VO compliant interfaces. It will allow them to justify the allocation of resources for its implementation and maintenance. Once the work on Version 1.0 is accomplished the working group will coordinate future development of the standard.

Current Standards

Standard Current Released Errata Next
ADQL - Astronomical Data Query Language v2.0 REC 2008-10-30 Errata  
DALI - Data Access Layer Interface v1.1 REC 2017-05-17 - 1.1 Next
Datalink v1.0 REC 2015-06-17 Errata 1.0 Next
SimDAL - Simulation Data Access Layer ** v1.0 REC 2017-03-20 -  
Simple Cone Search v1.03 REC 2008-02-22 Errata  
SIA - Simple image Access v2.0 REC 2015-12-23 -  
SLAP - Simple Line Access v1.0 REC 2010-12-09 -  
SODA - Server-side Operations for Data Access v1.0 REC 2017-05-17 Errata  
SSA - Simple Spectral Access v1.1 REC 2012-02-10 -  
TAP - Table Access Protocol v1.0 REC 2010-03-27 Errata 1.1 RFC 1.0 Next
TAPRegExt - A VOResource Schema Extension for Describing TAP Services * v1.0 REC 2012-08-27 -  
VOEvent Transport Protocol ** v2.0 REC 2017-03-20 -  

* Registry standard developed by the DAL working group.

** Interest group developed standard endorsed and administered by the DAL working group.

Ongoing Work

Standard Version Date Status Expected Release
SLAP - Simple Line Access Protocol v2.0 2019-04-09 Working Draft pending SSLDM-2.0
ObsLocTAP - Observation Locator Table Access Protocol v0.4 2019-02-27 Working Draft May 2020
ObjVisSAP - Object Visibility Simple Access Protocol v0.5 2019-03-19 Working Draft May 2020
ProvTAP - Provenance Table Access Protocol v0.1 2019-03-22 (internal) WD  
TAP - Table Access Protocol v1.1   RFC Summer 2019
Datalink DataLink-1_0-Next   Discussion  
DALI - Data Access Layer Interface DALI-1_1-Next   Discussion  
ADQL - Astronomical Data Query Language v2.1 2017-12-08 Working Draft  

WG Roadmap

DAL future

Current Activities

Idle or Abandoned

Past Activities

WG Roadmap

Notes on Defining a DAL Standard

This page contains some ideas and definitions to help frame the definition of DAL standards. To be discussed.

Notes on Defining new service parameters

This page contains some hints to help defining new service paremeters accordig to the 3 factor semantics.

Recommended reading

How to contribute

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf DAL-Cambridge-Report.pdf r1 manage 145.8 K 2003-10-23 - 21:01 UnknownUser Cambridge DAL WG Plenary Report
PowerPointppt DAL-Strasbourg-Report.ppt r1 manage 987.5 K 2003-10-23 - 20:35 UnknownUser Strasbourg DAL WG Plenary Report
Microsoft Word filedoc IVOA-DAL-Jul03.doc r1 manage 38.0 K 2003-07-23 - 06:10 UnknownUser DAL Progress Report July 03 by D. Tody
PDFpdf IVOA-DAL-Jul03.pdf r1 manage 19.3 K 2003-07-23 - 06:09 UnknownUser DAL Progress Report July 03 by D. Tody
PDFpdf TAP-Analysis.pdf r1 manage 419.7 K 2007-09-26 - 16:06 UnknownUser  
PDFpdf TAP-draft.pdf r1 manage 79.8 K 2007-09-26 - 16:06 UnknownUser  
PDFpdf dalsedspec.pdf r1 manage 1218.9 K 2003-10-18 - 16:16 UnknownUser SEDs & AVO prototype and ... (.pdf)
PowerPointppt dalsedspec.ppt r1 manage 284.5 K 2003-10-18 - 15:38 UnknownUser SEDs & AVO prototype and evolution to SSA
PDFpdf ranking-v01.pdf r2 r1 manage 100.9 K 2006-05-12 - 14:35 UnknownUser Ranking Query Result Sets
PowerPointppt sIAevol1.ppt r1 manage 37.5 K 2003-10-23 - 20:48 UnknownUser URL templating etc. proposals by F. Bonnarel
PDFpdf spie04-5493-47.pdf r1 manage 527.6 K 2004-07-01 - 15:16 UnknownUser SSA poster, status June 2004, 3x3 ft.
Microsoft Word filedoc ssa-v01-MD.doc r1 manage 4752.0 K 2004-09-25 - 14:12 UnknownUser SSA Spec. V0.1
XMLxml ssample1.xml r3 r2 r1 manage 31.3 K 2004-09-25 - 13:31 UnknownUser SSA sample SED serialization in VOTable format
XMLxml ssample20041021.xml r1 manage 31.8 K 2004-10-21 - 13:46 UnknownUser VOTable serialization; SSA data format
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Topic revision: r78 - 2019-04-18 - MarcoMolinaro
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