Oracle® Containers for J2EE Enterprise JavaBeans Developer's Guide 10g (10.1.3.5.0) Part Number E13981-01 |
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In a one-to-many relationship, an entity bean instance is related to multiple instances of another entity bean.
You specify a container-managed one-to-many relationship in the ejb-jar.xml
deployment descriptor (see "Using Deployment XML").
For more information, see "Configuring a Container-Managed Relationship Field for an EJB 2.1 Entity Bean With Container-Managed Persistence".
Example 14-9 shows the pair of <ejb-relationship-role>
elements that define a one-to-many bidirectional relationship between Order
and LineItem
. For a unidirectional relationship, you would omit the cmr-field
from the appropriate <ejb-relationship-role>
element.
Example 14-9 ejb-jar.xml for an EJB 2.1 Bidirectional One-to-Many Relationship
... <relationships> <ejb-relation> <ejb-relation-name>Order-LineItem</ejb-relation-name> <ejb-relationship-role> <ejb-relationship-role-name>order-has-lineitems</ejb-relationship-role-name> <multiplicity>One</multiplicity> <relationship-role-source> <ejb-name>OrderEJB</ejb-name> </relationship-role-source> <cmr-field> <cmr-field-name>lineItems</cmr-field-name> <cmr-field-type>java.util.Collection</cmr-field-type> </cmr-field> </ejb-relationship-role> <ejb-relationship-role> <ejb-relationship-role-name>lineitem-belongsto-order</ejb-relationship-role-name> <multiplicity>Many</multiplicity> <cascade-delete/> <relationship-role-source> <ejb-name>LineItemEJB</ejb-name> </relationship-role-source> <cmr-field> <cmr-field-name>order</cmr-field-name> </cmr-field> </ejb-relationship-role> </ejb-relation> ... <relationships>