SimDB = Simulation Database

SimDB is a specification for a Simulation Database. A SimDB implementation contains a database with (meta-)data describing simulations, their results, their provenance and various characteristics. The simulations are supposed to be those that produce a representation of 3+1D space, sometimes called "cosmological simulations", though they can be of any scale, from large scale structure of the universe down to solar systems. It has been a point of discussion whether we should open the spec up for all, or at least more types of simulations. This is an open issue. A SimDB also contains various types of post-processing products, as well as meta data identifying web services giving access to these simulations. The latter may, but are not restricted to SimDAP services.

The SimDB specification defines a protocol for an online service for querying and some management of this database. It has two components. One is a specialised TAP service, the other is a REST-like GET protocol to retrieve complete descriptions in XML form. Both of these are based on a data model for simulations, which is also part of this specification.

The full specification consists of a number of different documents. The latest versions of these as well as earlier ones, can be found in the specification directory under the theory/snapdm section of Norman Gray's Volute project on GoogleCode.

The theory/snapdmsection contains a lot more material than the specification alone. Most of this is the result of a project to create a demonstrator proto-type for the SimDB project. That project is in the process of being ported to the VO-URP project.

For the purpose of this specification one need only consult the specification sub directory. It contains the following documents:

  • DEPRECATED SimDB-note.doc (in rod, here is pdf): the Note describing SimDB, should be turned into a working draft at some point in the hopefully near future.
  • uml/SimDB_DM.xml: XMI document containing the UML data model on which the spec is based. Created by the 12.1 version of the community edition of MagicDraw UML drawing tool.
  • uml/SimDB_DM_INTERMEDIATE.xml: an XML document containing the so called "intermediate representation" of the data model. This is derived from the XMI model and is (much) easier to read and handle.
  • html/SimDB.html: HTML documentation fo rthe datamodel. Fully crosslinked and documented. Contains also the UTYPEs for the data model elements.
  • tap/SimDB_vodataservice.xml: XML document creating the TAP metadata for the SimDB database as a VODataservice.
  • tap/SimDB_tap_tableset.xml: XMl document containing the TAP metadata for the SimDB database as an "empty" VOTable (i.e. a TABLE for each public table, with FIELDs but no DATA)
  • xsd/: XML Schema files that defines how instances of the data model can be presented in XML.
    • xsd/SimDB_root.xsd: the "element" part of the SimDB schema set. It contains the valid root elements, i.e. the ones with which documents can be made. It depends on "type-schemas" that are all imported by this schema.
    • base.xsd: a schema defining some base types for use by other type definitions in the schema set.
    • The other XSD files in xsd/ and xsd/simdb/ and sub-directories define the (complex and simple)types. There is one type-schema document per XSD namespace, one XSD namespace per UML package.
  • xslt/: contains XSLT scripts that were used to generate the HTML, XSD and TAP documents from the UML model. They are here for informational purposes, and are not part of the specification. The build.xml ANT script in uml/ contains tasks for creating these documents.

Discussion pages

Other pages on the IVOA Wiki pertaining to this specification are

-- GerardLemson - 13 Mar 2009
-- HerveWozniak - 23 Jun 2008

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Topic revision: r14 - 2009-10-12 - GerardLemson
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