many-to-one relationship to non-PK field

[Tony Morris]

I'm trying to declare a foreign key relationship between two entities where the type is java.lang.String and the related entity field is not a primary key but is a unique field. If I attempt the same thing, but relating to a primary key field (by leaving off the property-ref attribute which defaults to the id), I have no problem.

I have narrowed down a test case in an attempt to solve this problem but to no avail. The problem is that 'schemaexport' will generate the two tables X and Y but will not create the relationship and I don't understand why (also, why it does the create the relationship when relating to a PK field). I am using the Microsoft type 4 driver for MS SQL Server 2000.

Please find below two source files annotated with XDoclet and corresponding mapping files. Any assistance is most appreciated.

/** 
 * @hibernate.class table="X" 
 */ 
public class X 
{ 
    private Long id; 
    private String uniqueField; 
 
    public X() 
    { 
        this(null); 
    } 
 
    public X(Long id) 
    { 
        this.id = id; 
    } 
 
    /** 
     * @hibernate.id generator-class="native" 
     */ 
    public final Long getId() 
    { 
        return id; 
    } 
 
    /** 
     * @hibernate.property 
     * @hibernate.column name="uniqueField" unique="true"
     */ 
    public final String getUniqueField() 
    { 
        return uniqueField; 
    } 
} 

/** 
 * @hibernate.class table="Y" 
 */ 
public class Y 
{ 
    private Long id; 
    private String field; 
 
    public Y() 
    { 
        this(null); 
    } 
 
    public Y(Long id) 
    { 
        this.id = id; 
    } 
 
    /** 
     * @hibernate.id generator-class="native" 
     */ 
    public final Long getId() 
    { 
        return id; 
    } 
 
    /** 
     * @hibernate.many-to-one name="field" class="X" property-ref="uniqueField" 
     */ 
    public final String getField() 
    { 
        return field; 
    } 
} 

<?xml version="1.0"?>
 
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 2.0//EN" 
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
 
<hibernate-mapping>
    <class
        name="com.tmits.web.re.schema.X"
        table="X"
        dynamic-update="false"
        dynamic-insert="false"
    >
 
        <id
            name="id"
            column="id"
            type="java.lang.Long"
        >
            <generator class="native">
            </generator>
        </id>
 
        <property
            name="uniqueField"
            type="java.lang.String"
            update="true"
            insert="true"
            access="property"
        >
            <column
                name="uniqueField" 
            />
        </property>
 
        <!--
            To add non XDoclet property mappings, create a file named
                hibernate-properties-X.xml
            containing the additional properties and place it in your merge dir.
        -->
 
    </class>
 
</hibernate-mapping>

<?xml version="1.0"?>
 
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 2.0//EN" 
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
 
<hibernate-mapping>
    <class
        name="com.tmits.web.re.schema.Y"
        table="Y"
        dynamic-update="false"
        dynamic-insert="false"
    >
 
        <id
            name="id"
            column="id"
            type="java.lang.Long"
        >
            <generator class="native">
            </generator>
        </id>
 
        <property
            name="field"
            type="java.lang.String"
            update="true"
            insert="true"
            access="property"
            column="field"
        />
 
        <many-to-one
            name="field"
            class="X"
            cascade="none"
            outer-join="auto"
            update="true"
            insert="true"
            access="property"
            property-ref="uniqueField"
            column="field"
        />
 
        <!--
            To add non XDoclet property mappings, create a file named
                hibernate-properties-Y.xml
            containing the additional properties and place it in your merge dir.
        -->
 
    </class>
 
</hibernate-mapping>