Is primary key a must for an entity bean

[NareshAnkuskani Kumar]

Is it mandatory to configure a primarykey in the deployment descriptor.

Not all the tables in the database contains a primarykey.

Suppose i have created an entity bean which represents a table that do not have a primary key.

Now my question is what can i put as a return type of 'ejbCreate' method in the above created entity bean & how do i configure the primarykey information in DeploymentDescriptor?

[Elton Kuzniewski]

Why you have a table without pk?!
[ March 11, 2008: Message edited by: Elton Kuzniewski ]

[Hong Anderson]

I don't sure, but why you don't need primary key?

How you find an entity without its identity? Or you don't want to find?

[NareshAnkuskani Kumar]

Thanks for your reply.

let me put the query in simple words.

Using entity beans is it possible to update or insert or delete a row in a database table which doesn't have a primary key?

[Joe San]

I don't think it's possible. Which object will you be updating? What would be the differentiator for the object that you are updating to that of the other objects in the table?

[Uchana Jackson]

Are you referring to 2.x or 3.0 spec? EJB3 supports 2.x entity beans.

for JPA, refer to section 2.1.4 of the JSR220 persistence spec.

you must have a PK for an entity class in JPA.

[Hong Anderson]

Originally posted by NareshAnkuskani Kumar:
Thanks for your reply.

let me put the query in simple words.

Using entity beans is it possible to update or insert or delete a row in a database table which doesn't have a primary key?

A table doesn't need to have a primary key, but in most cases a table should have one. If we don't have a primary key, how can we identify data in the table? That's not good.

[Roger Chung-Wee]

The Bean Provider must specify the primary key class for an
entity bean with bean-managed persistence, and may (but is not required to) specify the primary key class for an entity bean with container-managed persistence.

For a CMP bean, the PK can be inferred from the findByPrimaryKey method.