Something

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.dayspringTech.jgabler.hypersonicHibernateSpringExample" default-access="field">
	
	<class name="Book">
		<id name="id" column="book_id">
			<generator class="native"/>
		</id>
		<property name="title" column="title"/>
		<property name="dewey" column="dewey"/>
		<many-to-one name="category" column="category_id"
			class="com.dayspringTech.jgabler.hypersonicHibernateSpringExample.Category"
			not-null="true"/>
		<many-to-one name="reader" column="reader_id"
			class="com.dayspringTech.jgabler.hypersonicHibernateSpringExample.Reader"
			not-null="false"/>
	</class>
</hibernate-mapping>











<hibernate-mapping package="com.dayspringTech.jgabler.hypersonicHibernateSpringExample" default-access="field">
	
	<class name="Reader">
		<id name="id" column="reader_id">
			<generator class="native"/>
		</id>
		<property name="name" column="name"/>
<!-- WHEN I REMOVE THIS vvvvvvvvvvvvvvvvvvvvv -->
		<set name="books">                   
			 <key column="book_id"/>
			 <one-to-many class="Book"/>
		</set>
<!-- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-->
	</class>
	
</hibernate-mapping>