Technology Layer Cake

This diagram locates the involved technologies into or across logical layers that describes how certain components are further abstracted from the underlying RDF quadstore as each task demands more specialized features.

Ontology

As with any data service, MMS5 requires a schema in order to store and retrieve objects in the database. In MMS5, the database is an RDF quadstore. Whereas an RDF triple consists of a subject, predicate and object, an RDF quad is a triple with an additional context, the graph component. On the Web of Linked Data, named graphs have found a variety of uses and taken on different semantics. MMS5 follows one of the more common interpretations of named graphs by using them to partition sets of triples. These partitions serve two primary purposes: (1) to scope SPARQL queries/updates and (2) to dictate permission boundaries.

The diagram below illustrates the MMS5 Ontology as a collection of named graphs, each containing a set of classes with properties, and the relationships between classes which travel both within and across named graphs.

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For more information about the concepts referenced in the above diagram, see:

• Access Control

• Projects, Collections and Orgs

• Commits, Refs and Snapshots