Primary key in an EJB

[Seung Bang]

Hi,
How should I specify a primary key in an Entity bean, for which a db
table
really does not have a primary key?  To my understanding, a database
table with
a primary key can be represented with Entity beans as follows:
  ejbActivate():
       primKey = ctx.getPrimaryKey();

  ejbPassivate():
       primKey = null;

With that scheme, pooled beans can be reactivated with that primary key
later on.
What if a table does not have a primary key? How can it be reactivated
with what
primary key and how is it distinguished from other pooled beans? How
about
ejb-jar.xml descriptor? What do I put in the primary key field?
Thank you very much.

Seung,