Association Hibernate mapping

Question

I want to create a one-to-one relationship in Hibernate (XML mapping).

There are many examples showing how to do this. A popular example is a person with an address. The person table has got a foreign key to address. To be able to create a person record without an address you make the foreign key nullable.

That is not want I want. I want the opposite. In my database I have a table "Merchants" and a table "MerchantSettings". Every MerchantSettings record belongs to one Merchant and therefor has got a foreign key MerchantId. (In this way I can add merchant records without settings.)

In my code I have a class Merchant with a property Settings. What should the mapping look like?

(I do not want to have use 'component'. Table "MerchantSettings" has got it's own private key.)

Anybody knows how to do this?

[Update]

Because I do now want to use the same primary key as proposed by Karibasappa G C, I decided to add a foreign key to table "Merchants". I just make it nullable, so it is not required to have a MerchantSettings record (like the person/address examples).

It's not ideal, but I can work with it.

Thanks everybody.

Although it is not totally what I wanted, Marked Karibasappa G C's answer seems correct, and so I marked it as the accepted answer.

Answer 1

As per your requirement, you need to make merchant as the owner of the relationship. merchant should have auto generated primary key.

and merchantsettings should have a primary key which is the foreign key from merchant table.

so if above understanding is correct here is the mapping for you

 merchant.hbm.xml

        <hibernate-mapping package="com.kb.model">

            <class name="Merchant">
                <id name="id" column="id">
                    <generator class="identity" />
                </id>

                <property name="name" column="NAME" />
         <one-to-one name="merchantsettings" cascade="all"/>
            </class>
        </hibernate-mapping>

    merchantsettings.xml

    <hibernate-mapping package="com.kb.model">
        <class name="merchantsettings">

            <id name="id" column="id">
                <generator class="foreign">
                <param name="property">merchant</param>
                </generator>
            </id>


     <one-to-one name="merchant" constrained="true"/>
        </class>
    </hibernate-mapping>