Can someone please post an example of a simple one-to-one realationship between two classes, specifically the xml mapping.

I cannot get the example in the docs to work.

From the online docs.

For a primary key association, add the following mappings to Employee and Person, respectively.

<one-to-one name="person" class="Person"/>

<one-to-one name="employee" class="Employee" constrained="true"/>

If this is the example you are refering to then we will need to see more information.

All the examples on this site, and in the manual just say to add those 2 lines, but to where!?!

I have a very simple example, just two classes, BOOK and BARCODE. I want them to have the same primary key. Here's my mappings:

<hibernate-mapping>
<class
name="Barcode"
table="tbl_BARCODE"
dynamic-update="false"
dynamic-insert="false">

<id name="id"
column="ID"
type="java.lang.Long"
unsaved-value="-1">
<generator class="foreign">
<param name="property">Barcode</param>
</generator>
</id>

<one-to-one
name="id"
class="Book"
cascade="none"
outer-join="auto"
constrained="false"/>

<property
name="barcode_value"
type="java.lang.String"
update="true"
insert="true"
access="property"
column="BARCODE_VALUE"/>

</class>
</hibernate-mapping>

-----------------------------------------------------

<hibernate-mapping>
<class
name="Book"
table="tbl_BOOK"
dynamic-update="false"
dynamic-insert="false">

<id name="id"
column="ID"
type="java.lang.Long"
unsaved-value="-1">
<generator class="native">
</generator>
</id>

<property
name="name"
type="java.lang.String"
update="true"
insert="true"
access="property"
column="NAME"/>

<one-to-one
name="bc"
class="Barcode"
cascade="all"
outer-join="auto"
constrained="false"/>

</class>
</hibernate-mapping>

Do I need to add a reference from BOOK to BARCODE , and vice versa?

Thanks.

I *think* you only need to declare them both if you are going to have accessor methods in both classes:

book.getBarCode();

barCode.getBook();