C M P   2 . 0  

Relationship Declaration 

The declaration of relationships in the ejb jar.xml file is complicated and error prone.  The 

XML used to declared relationships is as inconsistent as Visual Basic syntax.  The best way 

to configure a relationship is to use a tool, such as 

XDoclet

, or cut and paste a working 

relationship. The ejb jar.xml declaration of the Organization Gangster relationship follows: 

Organization Gangster

org has gangsters

One

OrganizationEJB

memberGangsters

java.util.Set

gangster belongs to org

Many

GangsterEJB

organization

Listing 9 8, The ejb jar.xml Relationship Declaration 

After adding the cmr field abstract accessors and declaring the relationship, the relationship 

should be functional. For more information on relationships, see Chapter 4 of the JBossCMP 

Documentation, or Section 10.3 of the 

Enterprise JavaBeans Specification Version 2.0 Final 

Release

. The next section discusses the database mapping of the relationship. 

Relationship Mapping 

Relationships can be mapped using either a foreign key or a separate relation table. 

One to one and one to many relationships use the foreign key mapping style by default, and 

many to many relationships use only the relation table mapping style. The mapping of a 

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