Oracle® Containers for J2EE Enterprise JavaBeans Developer's Guide 10g (10.1.3.1.0) Part Number B28221-02 |
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In a many-to-many relationship, entity bean instances may be related to multiple instances of each other.
You specify a container-managed many-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 14-11 shows the pair of <ejb-relationship-role>
elements that define a many-to-many relationship between Teams
and Players
.
Example 14-11 ejb-jar.xml for an EJB 2.1 Many-to-Many Relationship
... <relationships> <ejb-relation> <ejb-relationship-role> <ejb-relationship-role-name>team-has-players</ejb-relationship-role-name> <multiplicity>Many</multiplicity> <relationship-role-source> <ejb-name>TeamEJB</ejb-name> </relationship-role-source> <cmr-field> <cmr-field-name>players</cmr-field-name> <cmr-field-type>java.util.Collection</cmr-field-type> </cmr-field> </ejb-relationship-role> <ejb-relationship-role> <ejb-relationship-role-name>player-has-teams</ejb-relationship-role-name> <multiplicity>Many</multiplicity> <relationship-role-source> <ejb-name>PlayerEJB</ejb-name> </relationship-role-source> <cmr-field> <cmr-field-name>teams</cmr-field-name> <cmr-field-type>java.util.Collection</cmr-field-type> </cmr-field> </ejb-relationship-role> </ejb-relation> ... <relationships>