How to implement SubType/SuperType in Oracle ?

Hi,

I have a supertype and three subtypes, as attached below, how is the best approach to implement it in Oracle (9i/10g) ?

Thank you for your help,
Krist

Supertype : Employee
  Employee_Number
  Employee_Name
  Address
  Employee_Type
  Date_Hired

SubType : Hourly_Employee
  Hourly_Rate

SubType : Salaried_Employee
  Annual_Salary
  Stock_Options

SubType : CONSULTANT
  Contract_Number
  Billing_Rate Received on Tue Jun 14 2005 - 05:51:49 CDT