2010-12-10 IVOA 2010, Nara

TAP implementation on SimDBApplication to DEUVO

Jonathan NormandVO-Paris Data Centre

IVOA 2010, Nara 2

Access to data of simulation Problematic:

o As many ways as types of simulation

o Steps depend on type of simulation

PDR: Protocol → Parameters StarFormat: Project → Experience → Snapshot → Postprocessings

As many ways as simulations and users

Solutions:o Ask data directly to the scientist

o Use the web UI provided for each simulation

Based on vo-urp framework: create database from SimDM, generate classes to access it, build web UI from them

o Use TAP layer

IVOA 2010, Nara 3

DEUVO Steps to access to data of DEUVO

o Select simulation

Depends on cosmology, code, physics...

o Select snapshot

o Select post processing

Depends on object, postprocessor and parameters

o Select properties

Use a different way than PDR or StarFormat

IVOA 2010, Nara 4

DEUVO – vo-urp solution From scratch

o Need to know many technologies (JAVA, JSP Servlet…) and classes generate by vo-urp (javadoc is available)

It is a long way

Adapt the web UI developed for StarFormat to DEUVO needso Steps differ too much so lot of code in classes has to be

modified

o SimDB of StarFormat and DEUVO are different so queries on database are different

Need to modify almost all queries

Try to use a more standardized way: TAP

IVOA 2010, Nara 5

DEUVO – TAP (1/2) Expected Metadata

o Provide TAP_SCHEMA or VOSI-tables output of SimDB

o SimDB created from SimDM: ~40 tables and many fields

Can everyone understand this kind of metadata?

IVOA 2010, Nara 6

DEUVO – TAP (2/2) Query data

o Write query in the request

o Example of query (without many constraints): SELECT s.id as id, s.publisherdid as publisherdid, s0.value_asquantity_value as mass,

s1.value_asquantity_value as x, s2.value_asquantity_value as y, s3.value_asquantity_value as z FROM snapshot s, objectcollection o , statistics s0, statistics s1, statistics s2, statistics s3 WHERE s.containerid = 6 AND o.containerid = s.id and s0.containerid = o.id and s1.containerid = o.id and s2.containerid = o.id and s3.containerid = o.id and s0.publisherdid = 'mass' and s1.publisherdid = 'x' and s2.publisherdid = 'y' and s3.publisherdid = 'z‘

o Corresponding VIEW (simple and readable):SELECT id, publisherdid, mass, x, y, z FROM tapview WHERE containerid = 6

Need to provide views for each allowed queries

IVOA 2010, Nara 7

DEUVO – TAP problems Access step by step is not possible Are people who not know the DM able to write a

query ?o Knowledge of simulation DM is mandatory to make a

meaningful query

Technical limit: length of URL (browser)

IVOA 2010, Nara 8

Conclusions Developer point of view:

o Need to provide views to help the end user

o Easy to add a TAP layer: handle TAP request and execute the query passed in parameters

User point of view:o Knowledge of DM and simulation helps to write queries

TAP is not self sufficiento Provide a step by step form on top of TAP

o Form helps to write queries for the user