When you initially create a CMP entity bean, you have the option of adding persistence fields, or attributes, to the bean.
However, if you later decide that you want to add a CMP field to the entity bean and perhaps define it as a key field, you can use the EJB deployment descriptor editor. For example, if you created a CMP entity bean named Customer, you might later want to add the CMP field email to the entity bean. Use the Bean page of the EJB deployment descriptor editor to add and remove CMP fields.
To add a CMP field with the EJB deployment descriptor editor: