First you would just define your enum.
public enum MyEnum
Yes = 1,
No = 2
Then you would add the property on your model as an int. (This is the just the ContentPartRecord. You would obviously need the ContentPart class as well)
public class MyPartRecord : ContentPartRecord
public virtual MyEnum YesNo
And finally to check that property, you would just cast your enum to an int and check it...
if(myPart.YesNo == (int)MyEnum.Yes)
// Do something
Hope that helps,