SingleSeveral.hbm.xml

<?xml version="1.0"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-lazy="false">

	<class 
		name="NHibernate.DomainModel.Single, NHibernate.DomainModel"
	>
		<composite-id>
			<key-property 
				name="Id" 
				length="32"
			/>
			<key-property 
				name="String" 
				length="32" 
				column="string_"
			/>
		</composite-id>
		
		<property name="Prop"/>
		
		<bag 
			name="Several" 
			inverse="true" 
			lazy="false" 
			cascade="all"
		> 
			<!--important: test for bidirectional with lazy="false" -->
			<key>
				<column 
					name="single_id" 
					not-null="true"
				/>
				<column 
					name="single_string" 
					not-null="true"
				/>
			</key>
			
			<one-to-many 
				class="NHibernate.DomainModel.Several, NHibernate.DomainModel"
			/>
		</bag>
	</class>
	
	<class 
		name="NHibernate.DomainModel.Several, NHibernate.DomainModel"
	>
		<composite-id 
			unsaved-value="any"
		>
			<key-property 
				name="Id" 
				length="32"
			/>
			<key-property 
				name="String" 
				length="32" 
				column="string_"
			/>
		</composite-id>
		
		<many-to-one 
			name="Single"
		>
			<column 
				name="single_id" 
				length="32"
			/>
			<column 
				name="single_string" 
				length="32"
			/>
		</many-to-one>
		
	</class>

</hibernate-mapping>