Currently system metadata consist of three "levels":

  1. QuadMapFormats

    are used to describe transformations of individual SQL values (or types of SQL values),

  2. QuadMaps

    refers to

    QuadMapFormats

    (via

    QuadMapValues

    ) and describe some "minimal" independent RDB2RDF transformations,

  3. QuadStorages

    organizes

    QuadMaps

    .

QuadStorages contains only "symlinks" to maps, if you drop a storage you don't drop all mappings inside. If you drop the DefaultQuadStorage or some other built-in thing, it can be safely recovered by DB.DBA.RDF_AUDIT_METADATA , with first parameter set to 1. This will keep your own data intact. However we recommend to write a script that declares all your formats, Linked Data Views and storages, to be able to reproduce the configuration after any failures.