In addition to explicitly named Properties, “code” and “id” attributes are special cases. Every entity in the Thésaurus – Concepts, Kinds, Properties, and Roles – has an associated “code” and “id.” These are used as unique identifiers in the Apelon development software, and, as such, are not defined explicitly as Roles or Properties. This required a hard-coded definition of both entities. They were defined as owl:AnnotationProperties, just like other Properties in the Thésaurus, and this allowed them to be attached to all of the definitions in the ontology. The example code above shows two Properties in addition to.
