@since J2EE1.3
The ejb-relationship-role element describes a role within a relationship.
There are two roles in each relationship. The ejb-relationship-role element contains an optional description; an optional name for the relationship role; a specification of the multiplicity of the role; an optional specification of cascade-delete functionality for the role; the role source; and a declaration of the cmr-field, if any, by means of which the other side of the relationship is accessed from the perspective of the role source. The multiplicity and relationship-role-source element are mandatory. The relationship-role-source element designates an entity-bean by means of an ejb-name element. For bidirectional relationships, both roles of a relationship must declare a relationship-role-source element that specifies a cmr-field in terms of which the relationship is accessed. The lack of a cmr-field element in an ejb-relationship-role specifies that the relationship is unidirectional in navigability and that entity bean that participates in the relationship is "not aware" of the relationship.

@invariant multiplicity != null
@invariant roleSource != null
@invariant Cascade delete can only be specified in an EJBRelationshipRole element in which the roleSource element specifies a dependent object class. 
@invariant Cascade delete can only be specified for an EJBRelationshipRole contained in an EJBrelation in which the other EJBRelationshipRole element specifies a multiplicity of One.

Example:
<ejb-relation>
  <ejb-relation-name>Product-LineItem</ejb-relation-name>
  <ejb-relationship-role>
    <ejb-relationship-role-name>product-has-lineitems</ejb-relationship-role-name>
    <multiplicity>One</multiplicity>
    <relationship-role-source>
      <ejb-name>ProductEJB</ejb-name>
    </relationship-role-source>
  </ejb-relationship-role>
...