I have a many-to-many association between two tables, but the association table has some extra columns (apart from the foreign keys).

This is how I would do it with XML mappings,

-------------------------------------------------------------------------
-- Test.hbm.xml --

...

<set name="TestProperties">
<key column="testID"/>
<composite-element class="TestProperty">
<property name="value" type="string" not-null="true"/>
<many-to-one name="type" class="PropertyType" not-null="true"/>
</composite-element>
</set>

...

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

but, I want to do it with Hibernate annotations. I think I should be able to define the TestProperty object with the extra data that I need and then have annotations in Test and PropertyType (plus possibly some more in TestProperty?) that will cause Hibernate to generate a TestProperty table that has a composite (Test's FK and PropertyType's FK) along with my extra columns. Can someone help? The code below is, of course, not complete. I was just hoping to present the code base and have someone help me annotate it.


@Entity
class Test
{
long id;
Set<TestProperty> properties = new Set<TestProperty>();

@Id
long getID() { return id; }

@OneToMany
Set<TestProperty> getProperties() { return properties; }

}

@Entity
class PropertyType
{
long id;
String name;
String metadata;

@Id
long getID() { return id; }

String getName() { return name; }
String getMetadata() { return metadata; }
}

// This is my association table
class TestProperty
{
String value;
PropertyType type;

String getValue() { return value; } // This is the extra column

@ManyToOne
PropertyType getPropertyType() { return type; }
}

For anyone interested, I stumbled upon the answer to my problem

@Entity
class Test
{
long id;
Set<TestProperty> properties = new Set<TestProperty>();

@Id
long getID() { return id; }

@CollectionOfElements
@JoinTable(name="TEST_PROPERTIES",joinColumns=@JoinColumn(name="TEST_ID"))
Set<TestProperty> getProperties() { return properties; }

}

@Entity
class PropertyType
{
long id;
String name;
String metadata;

@Id
long getID() { return id; }

String getName() { return name; }
String getMetadata() { return metadata; }
}

@Embeddable
class TestProperty
{
String value;
PropertyType type;

String getValue() { return value; } // This is the extra column

@ManyToOne
@JoinColumn(name="PROPERTY_TYPE_ID",nullable=false,updatable=false)
PropertyType getPropertyType() { return type; }
}