VizieR repository

Lessons learnt and issues

Repository implementation

Uses the VTOAI OAI-PMH2 Perl Data Provider library (H. Suleman, V. Tech)

Slightly modified to handle namespaces (vs:...) in elements

Answers OAI-PMH requests

verbs: Identify, ListSets, ListRecords, GetRecord

from, until

metadataPrefix (ivo_vor), identifier, resumptionToken (for long lists)

Repository implementation

http://vizier.u-strasbg.fr/viz-bin/registry/vizier/oai.pl

Latest version uses VOResource-v0.10

http://vizier.u-strasbg.fr/viz-bin/registry/vizier/oai_test.pl (in test... will move to oai.pl)

Only a repository (not full registry)

Dynamical content/answer

Resources are built on-the-fly from the contents of the VizieR DB

Uses VizieR metadata to fill resource elements

Catalogue 2:

Table1

Table2

Table3

Catalogue 3: Obsoleted by Cat34

Table

Catalogue 1:

Table1

Table2

+ Standardized metadata

+4300 catalogues

+10000 tables

VizieR structure

Catalogue 2:

Table1

Table2

Table3

Catalogue 3: Obsoleted by Cat34

Table

Catalogue 1:

Table1

Table2

+ Standardized metadata

Clone1

Catalogue 2:

Table1

Table2

Table3

Catalogue 3: Obsoleted by Cat34

Table

Catalogue 1:

Table1

Table2

+ Standardized metadata

Clone2

Metadata extraction

Metadata extraction

Metadata extraction

Metadata extraction

XML generation

Dynamical repository

The VizieR repository currently has no memory:

:o) always up-to-date

:o) easy to maintain (especially useful for HUGE collections like VizieR)

:o( not the OAI spirit (OAI is book-oriented: once a resource has existed, it must exist forever, even as 'deleted')

Need hard-coded XML version ?

What date should be used ?

Metadata change => created=? modified=?

Issues

Resources granularity

Currently, VizieR description at Table level only

Why not Catalogues ?

Create resources for Tables AND Catalogues ?

Make use of OAI Sets (4000 sets?)

How to handle hierarchy in a 'flat' registry?

Handling mirrors (no, not again?)

Dupplicate resources?

10,000 resources * 9 mirrors = 90,000 !

Dupplicate interfaces (and accessURL)?

Issues

Currently, all VizieR tables are presented as <resource xsi:type="vs:TabularSkyService">

(needed to describe the table columns)

For each table, there are different interfaces

WebBrowser (for humans)

ParamHTTP (retrieve VOTable)

If the table contains positions, I can make a ConeSearch on this table

new <resource xsi:type=...>?

new interface?

single resource VizieRConeSearch ?

thousands possible table-id as parameters!

Issues

How to describe a WS in an interface (methods?)

Relations between resources with <relatedResource>

Standard 'deprecatedBy' ?

Point to ivo-id and not Name?

VOTable Conclusions

SD

2004-09-07T10:49:58

SD