Data Types

OWL inherits most of RDF’s ability to specify XML string, numeric, datetime, and URI datatype values as data properties of an entity, and can compare data properties across entities (see here, here and here). OWL can also be used to specify constraints on string value length and content, and can specify numeric bounds on numbers. OBI currently focuses on reuse of RDF/XML datatypes to capture experimental data. Those who need further functionality may find other datatype representations useful (e.g. here).

A handful of the primitive datatypes from RDF which are used in OWL are discussed in this section. The possibility of user defined datatypes is avoided in favour of using enhanced value specifications to do the same work. Some examples below are expressed directly in OBI, while others can be constructed in an application ontology that draws on OBI components. Although OWL 2.0 isn’t suitable for doing all types of validation, we have shown how value specifications can be enhanced with basic numeric range and string content restrictions.