The Ontology Representation and Data Integration (ORDI) Framework is an open-source ontology middleware developed in JAVA. The major objectives of ORDI are:

  • Ontology language neutrality;
  • Integration of databases and other structured data-sources;
  • Support for heterogeneous reasoners and data-sources;
  • Interoperability with different data representation languages (e.g. OWL, WSML).

The second generation of ORDI (ORDI SG) was developed with partial funding by the EU IST projects TAO and TripCom. ORDI SG is foreseen as ontology management and data integration middleware in several other projects and products, among which: OWLIM, KIM, SemanticGov, MediaCampaign, RASCALLI

ORDI SG Tripleset Model

ORDI SG enables enterprise data integration via an RDF-like tripleset model. The ORDI SG Tripleset Model introduces basic notions and data-structures, which are to be used for ontology and data representation. The model is in no way ontology-specific – it allows representation of any structured data. It does not prescribe any sort of semantics and epistemology – therefore it is left to the higher levels, as well as to the specific implementations and applications, which are to impose a further interpretation over it. In other words, the ORDI SG tripleset model is neutral in terms of interpretation (or semantics) – it provides the freedom of choice of a data-source or the reasoning service to interpret its data accordingly in order to derive the desired results, i.e. to answer questions related to the existing data or to infer new data. We ground our data representation on an RDF-compatible data model, since it is well-founded and detached from the semantics of the various knowledge representations, ontology, and semantic Web languages used today.

ORDI SG Framework Features

The ORDI SG framework provides support for:

  • Feasible integration of different structured data sources including RDBMS (under development).
  • Backward compatibility with the existing RDF specifications and SPARQL query language.
  • Transactional operations over the model (under development).
  • Efficient processing and storage of meta-data or context information.
  • Grouping statements into manageable groups for the purposes of:
    • Definition of access rights and signing.
    • Management of sets of statements which correspond to single construct in a higher level language.
    • Transaction tracking and management.
    • Easy management of data from several sources within one and the same repository (or computational environment). Such are the cases of having data imported from different files (e.g. several ontologies).

ORDI SG Framework Architecture

The ORDI SG framework is designed on three layers:

  • ORDI Model Specification - providing an API for modeling and manipulating the ORDI SG tripleset model, as specified in the ORDI SG Specification
  • ORDI Model Implementation - providing a default implementation of the ORDI Model API, as well as other implementations that enable to persist the ORDI Model to different types of stores. Currently the default implementation uses TRREE, and there are also implementations over OWLIM and YARS.
  • Data Service Layer - providing specific services that allow translation of data represented in different languages to the ORDI SG data model, as well as storage of such data using some of the ORDI SG implementations. Currently the only available data service is WSMO4RDF, but in the near future we plan to provide also services for OWL data and for semantic annotations.


The latest release of ORDI SG, as well as the most recent snapshots can be downloaded from the project page on SourceForge

Documentation: ORDI SG Specification, Quick Start Guide, on SourceForge .