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Configuration

 

This section covers specific configuration options related to RDF. For all other settings such as evaluation methods or persistency, see the main OntoBroker documentation.

For OntoBroker RDF the ontology language has to be RDF.

OntologyLanguage = RDF

If necessary, you can activate additional RDF(S) entailment rules. There are two optional groups defined to infer implicit defined classes and/or properties. The default setting for both options is off.

RDF.Infer.Classes = on|off

RDF.Infer.Properties = on|off

Finally, if query performance is more important than storage consumption, all of the RDF(S) entailment rules can be materialized. By default, materialization is switched off.

MaterializeAxioms = on|off

Materialize.RDF.Entailment.Domain = on|off

Materialize.RDF.Entailment.Range = on|off

Materialize.RDF.Entailment.PropertyTransitivity = on|off

Materialize.RDF.Entailment.PropertyInheritance = on|off

Materialize.RDF.Entailment.ClassInheritance = on|off

Materialize.RDF.Entailment.ClassTransitivity = on|off

Materialize.RDF.Helper.Subclass = on|off

Materialize.RDF.Helper.Subproperty = on|off

Materialize.RDF.Helper.Generic = on|off

Materialize.RDF.Helper.TypeTemp = on|off

Materialize.RDF.Helper.Type = on|off

Materialize.RDF.PropertyDef.ByPredicate = on|off

Materialize.RDF.PropertyDef.ByDomain = on|off

Materialize.RDF.PropertyDef.ByRange = on|off

Materialize.RDF.PropertyDef.BySubpropertySubject = on|off

Materialize.RDF.PropertyDef.BySubpropertyObject = on|off

Materialize.RDF.ClassDef.ByType = on|off

Materialize.RDF.ClassDef.ByDomain = on|off

Materialize.RDF.ClassDef.ByRange = on|off

Materialize.RDF.ClassDef.BySubclassSubject = on|off

Materialize.RDF.ClassDef.BySubclassObject = on|off

The best evaluation method to choose is highly dependent on the characteristics of the given data and queries. The default settings should work fine for most use cases. For further optimization, the following settings may be tested alternatively:

Set evaluation method to Dynamic Filtering 2:

EvaluationMethod = DynamicFiltering2

Set evaluation method to Disjunctive Magic Set in combination with bottom-up evaluator Bottom-Up 2:

EvaluationMethod = DisjunctiveMagicSet

BottomUpEvaluator = BottomUp2

Activation of module names ground:

ModuleNamesGround = on

Please note that some restrictions apply for concept and attribute names ground. See the FAQ for more details. Note in addition that some filter expressions are not bottom-up save. If such filter expressions are required, use some top-down based evaluation like Dynamic Filtering 2 since bottom-up evaluation is not possible in such a case.