EJB relation one:many ??

[Georg Joo]

Hi

I have a prblem to understand the EJB relations.
Example: the first table (invoice) has a key "Number" and the second table
(invoicepositions) has the key "Number, Posnumber".

The reltaion is 1:many unidirectional.

How have I to solve this situation ? Has Bean invoice a CMR field "Number" ? This field this a CMP field (!?). Have I tho declare a CMR field "positions"?
What's the right way to do this ?

Thanks

Georg

[Valentin Crettaz]

Actually, in the Invoice bean class, you should declare the following method that represents the invoicePositions CMR field:
public abstract Collection getInvoicePositions();
The returned Collection will contain InvoicePositionLocal references.

And now, your deployment descriptor should look like:

...
      <ejb-relation>
         <ejb-relation-name>Invoice-InvoicePosition</ejb-relation-name>
 
         <!-- unidirectional -->
         <ejb-relationship-role>
            <ejb-relationship-role-name>
                One-Invoice-to-Many-InvoicePosition
            </ejb-relationship-role-name>
            <multiplicity>One</multiplicity>
            <relationship-role-source>
               <ejb-name>Invoice</ejb-name>
            </relationship-role-source>
            <cmr-field>
               <cmr-field-name>invoicePositions</cmr-field-name>
               <cmr-field-type>java.util.Collection</cmr-field-type>
            </cmr-field>
         </ejb-relationship-role>
         <ejb-relationship-role>
            <ejb-relationship-role-name>
               Many-InvoicePosition-to-One-Invoice
            </ejb-relationship-role-name>
            <multiplicity>Many</multiplicity>
            <relationship-role-source>
               <ejb-name>InvoicePosition</ejb-name>
            </relationship-role-source>
         </ejb-relationship-role>
      </ejb-relation>
...

Note that you can freely change the content of ejb-relation-name, ejb-relationship-role-name.

I hope this helps

[Georg Joo]

Yes, this was the answer I need.

Thanks

Georg

[Valentin Crettaz]

And depending on your application server you still have to write the vendor-specific deployment descriptor for mapping the CMR fields to the proper columns in your database.

Or you use XDoclet and you write everything in the source file
[ July 28, 2004: Message edited by: Valentin Crettaz ]

[Georg Joo]

Hi

Can I map the CMR Field getInvoicePositions() to a PrimaryKey field ?
I get always an error.
Is it possible to use Number of the PK for the CMR field ??? (If it is possible, then I have to read the jonas documentation twice).

Or have I to insert an own column for the CMR filed, that holds the same value as the Number of the PK (I thik not)???

Thanks

Georg