OWLIM-SE Fact Sheet

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This documentation is NOT for the latest version of GraphDB.

Latest version - GraphDB 7.1

OWLIM Documentation

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OWLIM-SE is the commercial edition of OWLIM – a high-performance semantic repository created by Ontotext. It is implemented in Java and packaged as a Storage and Inference Layer (SAIL) for the Sesame RDF framework. OWLIM-SE is a native RDF rule-entailment and storage engine. The supported semantics can be configured through rule-set definition and selection. Included are rule-sets for OWL-Horst [25], unconstrained RDFS [11] with OWL Lite [14] and the OWL2 profiles RL and QL [30][31]. Custom rule-sets allow tuning for optimal performance and expressivity.
Reasoning and query evaluation are performed over a persistent storage layer. Loading, reasoning and query evaluation proceed extremely quickly even against huge ontologies and knowledge bases.
OWLIM-SE can manage billions of explicit statements on desktop hardware and can handle tens of billions of statements on commodity server hardware. According to public evaluation data, OWLIM-SE is the most scalable OWL repository currently available.
OWLIM's web site, http://www.ontotext.com/owlim, provides extensive information and references regarding support contacts and mailing lists, documentation and latest performance benchmarks.


The key features of the current release of OWLIM-SE can be summarised as follows:

  • The most scalable semantic repository in the World, both in terms of the volume of RDF data it can store and the speed with which it can load and do inferencing;
  • Pure Java implementation, ensuring ease of deployment and portability;
  • Compatible with Sesame 2, which brings interoperability benefits and support for all major RDF syntaxes and query languages;
  • Customisable reasoning, in addition to RDFS, OWL-Horst, and OWL 2 RL support;
  • Optimized owl:sameAs handling, which delivers dramatic improvements in performance and usability when huge volumes of data from multiple sources are integrated.
  • Clustering support brings resilience, fail-over and scalable parallel query processing;
  • Geo-spatial extensions for special handling of 2-dimensional spherical data allowing data using the WGS84 RDF vocabulary to be indexed and processed quickly using a variety of special geometrical query constructions and SPARQL extensions functions;
  • Full-text search support, based on either Lucene or proprietary search techniques;
  • High performance retraction of statements and their inferences – so inference materialisation speeds up retrieval, but without delete performance degradation;
  • Powerful and expressive consistency/integrity constraint checking mechanisms;
  • RDF rank, similar to Google's PageRank, can be calculated for the nodes in an RDF graph and used for ordering query results by relevance, visualisation and any other purposes;
  • RDF Priming, based upon activation spreading, allows efficient data selection and context-aware query answering for handling huge datasets;
  • Notification mechanism, to allow clients to react to statements in the update stream.

Interfaces, Standards, Requirements

OWLIM-SE is a Java library without user interface. Sesame's Web UI applications can be used.
Interfaces (API, Web Services): OWLIM implements the SAIL interfaces of Sesame, so it can be used locally (embedded) or remotely via the Sesame HTTP server.
Platform: Java JRE version 1.5 onwards (both 32-bit and 64-bit versions). If custom rule-sets are used then a Java JDK version 1.6 inwards is required.
Supported standards: OWLIM is bound to the data and query standards supported by Sesame. RDF is the basic data standard; the supported query languages are: SeRQL, SPARQL, RQL, RDQL.
Syntaxes: The import and export of all major RDF syntaxes (XML, N3, N-Triples, Turtle, TRIG, TRIX) is supported through Sesame.
Semantics: OWLIM supports RDFS, OWL Horst, OWL Max (RDFS with that part of OWL Lite that can be captured in rules), OWL2 QL and OWL2 RL, along with the ability to create customised rule-sets.
Required Libraries: Sesame (http://www.openrdf.org) is an open-source RDF database with support for RDF inference and querying. OWLIM-SE has been tested with Sesame release 2.4.0.


OWLIM-SE is available under an RDBMS-like commercial license on a per-server-CPU basis; it is neither free nor open-source. To purchase a license or obtain a free copy for research or evaluation, please, contact OWLIM-info@ontotext.com.

Installation and Usage

OWLIM-SE is distributed as a ZIP archive that contains OWLIM-SE's compiled jar's, all required libraries, configuration files, documentation, sample code and data. OWLIM-SE is designed to be used as a Storage and Inference Layer (SAIL) for the Sesame openRDF framework – no OWLIM specific interfaces are intended for external use. Sesame 2 libraries are included as part of the OWLIM distribution; the complete Sesame distribution can be downloaded from http://www.openrdf.org. Use of the rule-compiler (i.e. custom rule-sets) requires the Java Development Kit (JDK) version 1.6 or later, otherwise a Java Runtime Environment (JRE) version 1.5 or later is required.
The easiest way to get to know OWLIM-SE is to explore the Getting Started application that is included in the release package and documented in section 8.2 – it allows one to load data, evaluate queries, and experiment with the configuration parameters, without the need to understand and compile Java code.
The installation section provides all the information necessary to setup OWLIM-SE with Sesame.


OWLIM uses Sesame as a library, taking advantage of its APIs for storage and querying, as well as the support for a wide variety of query languages (e.g. SPARQL and SeRQL) and RDF syntaxes (e.g. RDF/XML, N3, Turtle).

The development of OWLIM is partly supported by SEKT, TAO, TripCom, LarKC, and other FP6 and FP7 European research projects.

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