The Protégé Short Note (Part 3)
OWL Properties
There are two main types of properties in OWL as Object Properties and Datatype Properties. Apart from this there are types of properties called Annotation Properties.All these types of properties represent relationships.
Remarks:
- Object properties and Datatype properties can be marked as Annotation properties.(If we want)
- As a convention “has” or “is” are used as prefixes for Object and Datatype properties.
1. Object Properties
As shown above, Object properties represent relationships between two individuals. They can be created using the Object Properties tab in Protégé. Click on owl:topObjectProperty and then on newObjectProperty button if you want to add only one property or right click and Add sub properties… if you want to add a hierarchy of properties as we did in adding classes before.
As a convention has or is used as prefixes for the properties.
We can now create the hasIngredient property which has two sub properties hasTopping and hasBase.
1.1 Inverse properties.
Every object property may have a corresponding inverse property. So, as shown here if a property link individual A to B, it’s inverse property link individual B to A. We can create inverse properties using the inverse of button in the property description view (see above).
Create the inverse properties for the hasTopping and hasBase as, isToppingOf and isBaseOf.
1.2 Characteristics of OWL Object properties.
Now I’m are going to talk about the characteristics of OWL object properties. We can specify these characteristics using the Property Characteristic View shown in this figure. I’m going to explain each characteristic one by one by describing what each of them is for.
In the next part we are going to define classes with the use of these object properties and a new concept called restrictions.
