The ORDI SG architecture is specified in terms of APIs, which determine the major components and define the interfaces for both usage and extension of an implementation of ORDI SG.

The architecture is defined as an extension of the Sesame 2.0, Alpha-3, architecture. Sesame is one of the most mature, popular, and efficient, RDF management frameworks. In ORDI SG there is a central Store interface, that together with its successors provide methods for storage, retrieval and modification of data represented with respect to ORDI SG Tripleset Model. Store interfaces can be stacked on top of each other, to allow for flexible extension of the functionality.

The above figure presents the ORDI SG framework as composed by core APIs, components and store adapters. The core components and APIs define the main functionality of the framework by introducing set of Java interfaces and implementations to interact with them. The architecture defines the following APIs and components:

• Sesame Model is a lightweight API. It is responsible to describe generic concepts like RDF statement, resource, literal, blank node and URI. ORDI SG framework reutilizes the generic packages org.openrdf.model part of Sesame in order to ensure compatibility with the high performance RIO parser implementations;
• Store API describes how the different framework components to interact with the functionality offered by the contained stores. A design principle is to allow no components to interact with implementation outside of its component scope;
• Store Manager is some sort of data store registry. It provides basic operation to manipulate the available configured data stores, based on the functionality they implement;
• Monitor API is still undefined. The requirements towards it are to provide sophisticated mechanism to trace internal system functionality and to optimize the operation over the framework;
• Query Engine processes SPARQL based queries and creates an executable conjunction of patterns to be matched against any arbitrary data store;
• Security Manager is component responsible to define the security across the different system parts. Its functionality is still undefined, because of lack of significant requirements.

The ORDI SG store adapters realize the interface defined by the Store API. They could be divided into two main groups concerning their added functionality to the framework:

• Adapters to provide data. They ensure a mapping between an interface part of the Store API and another one supported by third-party persistent store. Such adapters are the Sesame adapter to map the TripleSet data model to SAIL, or a RDBMS adapter to transform legacy database information data set to ontology, based on specified schema. The mapping depending on the implementation could be complete or partial; and supported in one or both directions.
• Adapters to provide new functionality. They use adapters that provide data and introduce new functionality. Example for functional adapter is the Multiplex Adapter that implements the MultiTripleSetModel to union the information located in several tripleset stores.