Entity has no sharepoint-specific fields like "SPFieldUrlValue".
There are two special field types:
Because of this, it is very simple to change aplication data source from MOSS to SQL, which could be the really hard task with different architecture.
[Serializable]
public class Employee : EntityBase
{
public string Name { get; set; }
public DateTime BirthDate { get; set; }
public bool? IsActive { get; set; }
public decimal Priority { get; set; }
public PersonInfo Superior { get; set; } // special person field type
public List<LookUpItem> Divisions { get; set; } // special entity reference field type
}