This figure shows the mapping for a one-to-one relationship. A sample `ejb-jar.xml` file is shown with the following code:

    <relationships>
    ...
    <ejb-relation>
    ...
       <multiplicity>One</multiplicity>
       <relationship-role-source>EmpBean</relationship-role-source>
       <cmr-field>
          <cmr-field-name>address</cmr-field-name>
       </cmr-field>
    ...
    </ejb-relation>
    <ejb-relation>
    ...
       <relationship-role-source>AddressBean</relationship-role-source>
    ...
    </ejb-relation>

A sample `orion-ejb-jar.xml` file is also shown, with the following code:

    <entity-deployment name="EmpBean"...
    <cmp-field-mapping name="address">
       <entity-ref home="AddressBean">
          <cmp-field-mapping name="address" persistence-name="addressPK" />
       </entity-ref>
    </cmp-field-mapping>
    ...
    </entity-deployment>
    entity-deployment name="AddressBean"...
    ...
    <cmp-field-mapping name="empNo">
       <entity-ref home="EmpBean">
          <cmp-field-mapping name="empNo" persistence-name="empno" />
       </entity-ref>
    </cmp-field-mapping>
    ...
    </entity-deployment>

There are three arrows in this illustration:

- From the `<cmr-field-name>address</cmr-field-name>` line in `ejb-jar.xml` to the `<cmp-field-mapping name="address" persistence-name="addressPK" />` line in `orion-ejb-jar.xml`.

- From the `<cmr-field-name>address</cmr-field-name>` line in `ejb-jar.xml` to the `<cmp-field-mapping name="address">` line in `orion-ejb-jar.xml`.

- From the `<ejb-name>AddressBean</ejb-name>` line in `ejb-jar.xml` to the `<entity-ref home="AddressBean">` line in `orion-ejb-jar.xml`.

There is also a note pointing to the `<cmp-field-mapping name="address" persistence-name="addressPK" />` line in `orion-ejb-jar.xml` indicating that this is the name of the database column for the foreign key.