The tables on this page summarise decisions taken during first the SNAP, then the SimDB projects. These issues were discussed mainly in a small core group of developers (GL, Laurent Bourges, Rick Wagner, Claudio Gheller, Franck
LePetit, Herve Wozniak with input from Patrizia Manzato, Mireille Louys, Igor Chillingarian, Norman Gray and participants of a small workshop, Apruil 2007 in Garching).
For the further development of SimDB (and possibly SimDAP) it may be useful to list these and possibly reevaluate them. The issues are subdivied in a few subjects:
Approach to SimDB (starting with SNAP)
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Comment |
SNAP data model complex, queryData requires registry-like approach |
Discussed in April 2007 SNAP meeting of core participants (up till then), Garching |
SNAP is a DAL protocol for simulations1 |
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initiated in theory workshop in Cambridge 2006 |
SNAP follows SSA:data model + protocol |
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(Victoria interop, 2006) |
SNAP separated into SimDB and SimDAP |
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formally announced in 2008 Trieste interop, agreed by "tiger team" before |
SimDB is a protocol for finding interesting simulations and postprocessing experiments and their results |
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SimDB implements "queryData" part of "simple" DAL protocols |
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"getData" part is implemented by SimDAP or custom services |
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1 bla
SimDB data modelling methodology
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Comment |
SimDB/DM represented in UML class diagram |
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UML aspect follows decision in Cambridge interop 2003. Class diagram seems obvious (?) |
SimDB/UML is self documenting2 |
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This was decision of core designers (GL, RW, LB), presented in 2008 Trieste Interop |
SimDB/DM's UML stored as XMI document (ASCII) |
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XMI is standard XML format for representing UML documents. |
SimDB uses MagicDraw Community Edition 12.1 for the XMI |
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Freely available tool, ESO has commercial version. Should not be necessary to specify a tool, as XMI should deal with that, but in practice useful to "insist" on one |
SimDB/DM uses a predefined UML profile |
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Aimed to simplify models and promote interoperability by presenting uniform DM langugage fo the IVOA. Restriction + extension of UML, currently informal (Appendix in Note) + formal (a UML2 profile generated by ESO, updated in course of design). |
Propose an intermediate XML format for representing DMs following profile. |
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In practice very useful. Very much more readable than XMI. in principle hand-editable. Core of VO-URP TAP/XSD/HTML/UTYPE/Java/DDL/... generation. |
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2All entities and classes must be properly documented. SimDB/Note gives background and context, UML model
should be sufficient to define complete model.
SimDB/DM contents
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Comment |
SimDB aims at describing "large/3+1D simulations" |
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In principle only Snapshot iso more generic Result class is explicitly 3+1D |
"getData" services can be foud in SimDB |
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SimDB/TAP
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SimDB is a TAP service |
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first discussed April 2007 Garching |
SimDB's TAP_SCHEMA predefined |
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Allows for integration: same ADQL can be sent to all SimDB services. |
SimDB/TAP_SCHEMA derived from SimDB/DM using predefined OR-mapping rules |
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SimDB/TAP's OR mapping rules uses |
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SimDB and Registry