Ontology-Based Database Approach for Handling Preferences - Data Warehousing Design and Advanced Engineering Applications - page 263

Table 12. Definition of FUZZY_PREFERENCE and its instantiation

FUZZY_PREFERENCE
ENTITY FUZZY_PREFERENCE
SUBTYPE OF (INTERPRETED_PREFERENCE);
interpreted_by: LIST [1:?] OF PROB_VALUE;
pref_attributes: LIST[1:?] OF PREFERENCE_URI;
END ENTITY;

Table 13. Definition of UNINTERPRETED_PREFERENCE and its instantiation

UNINTERPRETED_PREFERENCE
ENTITY UNINTERPRETED_PREFERENCE
SUBTYPE OF (PREFERENCEDEFINITION);
interpreted_by: SET [1:?] OF PROPERTY_OR_CLASS_INSTANCE;
pref_attributes: LIST[1:?] OF PREFERENCE_URI;
END ENTITY;

Ontology Preference Link

we need to handle it into the OntoDB system.

Handling the Model of
Preferences into OntoDB

When all types of preferences in our preferences
model have been defined, we need to link them to the
ontological model. To do this, we use the ontology
preference relationship. This relationship allows to
attaching a particular preference to a given ontologi-
cal entity, being either a class or a property.
The PROPERTY_OR_CLASS resource rep-
resents data elements of the model of the ontology
that we refer to. It represents both the data and the
domain knowledge (described in an ontology) inde-
pendently of any implementation model. Moreover,
it is modelled independently from any specific model
of ontology (e.g. OWL, F-Logic (Kifer et al., 1995),
PLIB). The EXPRESS-G representation of the Pref-
erence_Link is represented in Figure 5.
Once our preference model is formally defined,

Our approach is implemented by extending the
OntoDB system. OntoDB offers the necessary
facilities to store in the same infrastructure both
ontologies and the preference model. Thanks to
the use of the OntoQL language, the manipulation
of these different components becomes easier.

OntoDB Extension with Preferences

The extension of OntoDB handling preferences
consists first in creating the entity PREFERENCE
using the CREATE clause of the OntoQL language
as schematised in the following expression

Table 14. Definition of CONTEXT_BASED PREFERENCE and its instantiation

Context_Based_PREFERENCE
ENTITY Context_Based_PREFERENCE
SUBTYPE OF (PREFERENCE);
context_value: PROPERTY_OR_CLASS_INSTANCE;
preference: PREFERENCE_ DEFINITION;
pref_attributes: LIST[1:?] OF PREFERENCE_URI;
END ENTITY