EntityBean and Relational database problem

[ericmacau]

Hello,

Would you please to teach me how can I implement the following table relations in EJB(CMP).


ITEM
======================
itemNo VARCHAR(30)
itemName VARCHAR(100)
desc VARCHAR(500)


BOOK_ITEM
======================
itemNo VARCHAR(30)
ISBN VARCHAR(50)


CD_ITEM
======================
itemNo VARCHAR(30)
ARTIST VARCHAR(100)



BOOK_ITEM ------ ITEM -------- CD_ITEM

the ITEM will links to the BOOK_ITEM and CD_ITEM by using the key itemNo.

[mozheyko_d]

######################
ejb-jar-xml
######################

.........



<ejb-relation>

<ejb-relation-name>
item-book-item
</ejb-relation-name>

<ejb-relationship-role>

<ejb-relationship-role-name>
item-has-book-items
</ejb-relationship-role-name>
One
<relationship-role-source>
<ejb-name>ItemBean</ejb-name>
</relationship-role-source>
<cmr-field>
<cmr-field-name>itemBookItems</cmr-field-name>
<cmr-field-type>java.util.Set</cmr-field-type>
</cmr-field>
</ejb-relationship-role>
<ejb-relationship-role>
<ejb-relationship-role-name>
book-item-belongs-to-item
</ejb-relationship-role-name>
Many
<cascade-delete/> <!-- if you need -->
<relationship-role-source>
<ejb-name>BookItemBean</ejb-name>
</relationship-role-source>
<cmr-field>
<cmr-field-name>itemNo</cmr-field-name>
</cmr-field>
</ejb-relationship-role>
</ejb-relation>

<ejb-relation>

<ejb-relation-name>
item-cd-item
</ejb-relation-name>

<ejb-relationship-role>

<ejb-relationship-role-name>
item-has-cd-items
</ejb-relationship-role-name>
One
<relationship-role-source>
<ejb-name>ItemBean</ejb-name>
</relationship-role-source>
<cmr-field>
<cmr-field-name>itemCDItems</cmr-field-name>
<cmr-field-type>java.util.Set</cmr-field-type>
</cmr-field>
</ejb-relationship-role>
<ejb-relationship-role>
<ejb-relationship-role-name>
book-item-belongs-to-item
</ejb-relationship-role-name>
Many
<cascade-delete/> <!-- if you need -->
<relationship-role-source>
<ejb-name>CDItemBean</ejb-name>
</relationship-role-source>
<cmr-field>
<cmr-field-name>itemNo</cmr-field-name>
</cmr-field>
</ejb-relationship-role>
</ejb-relation>
....
######################
jbosscmp-jdbc-xml
######################

.....

<ejb-relation>
<ejb-relation-name>
item-book-item
</ejb-relation-name>
<foreign-key-mapping/>
<ejb-relationship-role>
<ejb-relationship-role-name>
item-has-book-items
</ejb-relationship-role-name>
<key-fields>
<key-field>
<field-name>
itemNo
</field-name>
<column-name>
itemNo
</column-name>
</key-field>
</key-fields>
</ejb-relationship-role>
<ejb-relationship-role>
<ejb-relationship-role-name>
book-item-belongs-to-item
</ejb-relationship-role-name>
<key-fields/>
</ejb-relationship-role>
</ejb-relation>


<ejb-relation>
<ejb-relation-name>
item-cd-item
</ejb-relation-name>
<foreign-key-mapping/>
<ejb-relationship-role>
<ejb-relationship-role-name>
item-has-cd-items
</ejb-relationship-role-name>
<key-fields>
<key-field>
<field-name>
itemNo
</field-name>
<column-name>
itemNo
</column-name>
</key-field>
</key-fields>
</ejb-relationship-role>
<ejb-relationship-role>
<ejb-relationship-role-name>
cd-item-belongs-to-item
</ejb-relationship-role-name>
<key-fields/>
</ejb-relationship-role>
</ejb-relation>
...