text: **Exercise 31: Create a Datatype Restriction that Every Pizza hasCaloricContent**
  
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  1. Navigate to the Classes major tab. 
  
  2. Select the Pizza class. 
  
  3 Click on the (+) icon next to the SubClass Of field in the Description view. This time let’s use the Data 
  restriction tab. Navigate to and select hasCaloricContent in the Restricted property view. In the 
  Restriction filler view scroll down to xsd:integer and select it. The Restriction type should be set to the 
  default which is Some. If it isn’t use the menu to change it. Your UI should look like figure 5.6. Click 
  OK. 
  
  4. Note that you also could have selected Exactly 1 because a Pizza can only have one caloric content but 
  since you already defined the property to be functional this isn’t necessary and either Some or Exactly 1 
  have the same effect. Just as Protégé usually provides several ways to enter the same information in the 
  user interface OWL often provides different ways to provide the same information in your model. The 
  nice thing is the reasoner lets you not worry so much about which way you do it, as long as your 
  definitions are consistent. 