<hibernate-mapping package="model.message">
    <class name="Template" table="template" discriminator-value="0">
        <id name="id" column="id" type="long" unsaved-value="-1">
            <generator class="native">
                <param name="sequence">template_seq</param>
            </generator>
        </id>
       
        <discriminator column="discriminator" type="integer"/>
       
        <version name="version" column="version" type="integer" unsaved-value="negative"/>
       
        <property name="name" column="name" type="string"/>
               
        <subclass name="model.message.email.EmailTemplate" discriminator-value="1">
            <set name="attachments" inverse="true" cascade="all-delete-orphan">
               
                <key column="email_template"/><!-- PROBLEM -->
                <one-to-many class="message.email.Attachment"/>
            </set>
            <list name="emailTemplateParts" inverse="true" cascade="all-delete-orphan">
                <key column="email_template" not-null="true" update="false"/>
                <index column="list_index" type="integer"/>
                <one-to-many class="model.message.email.EmailTemplatePart"/>
            </list>
            <join table="email_template">
                <key column="id"/>
                <property name="from" column="from_addresses" type="string"/>
                <property name="to" column="to_addresses" type="string"/>
                <property name="cc" column="cc_addresses" type="string"/>
                <property name="bcc" column="bcc_addresses" type="string"/>
                <property name="subject" column="subject" type="string"/>
            </join>
            <subclass name="model.message.email.NewsletterTemplate" discriminator-value="2">
                <join table="newsletter_template">
                    <key column="id"/>
                    <many-to-one name="newsletter" column="newsletter" class="model.newsletter.Newsletter"/>
                </join>
            </subclass>
        </subclass>
    </class>
</hibernate-mapping>

<hibernate-mapping package="model.document">
    <class name="Document" table="document" discriminator-value="0">
        <id name="id" column="id" type="long" unsaved-value="-1">
            <generator class="native">
                <param name="sequence">document_seq</param>
            </generator>
        </id>
       
        <discriminator column="discriminator" type="integer"/>
       
        <version name="version" column="version" type="integer" unsaved-value="negative"/>
       
        <many-to-one name="input" column="input" class="model.source.Input" outer-join="false" lazy="true"/>
        <property name="ssn" column="ssn" type="string"/>
        <property name="name" column="name" type="string" not-null="true"/>
        <property name="created" column="created" type="timestamp"/>
        <property name="viewed" column="viewed" type="timestamp"/>
        <property name="contentType" column="content_type" type="string" not-null="true"/>
        <property name="contentLength" column="content_length" type="long"/>
        <many-to-one name="content" column="content" class="Content" lazy="true" outer-join="false" cascade="all-delete-orphan"/>
       
        <subclass name="Garnishment" discriminator-value="1">
            <join table="garnishment">
                <key column="id"/>
                <property name="notificationDate" column="notification_date" type="timestamp"/>
                <property name="type" column="type" type="integer"/>
            </join>
        </subclass>
        <subclass name="model.message.email.Attachment" discriminator-value="2">
            <join table="attachment">
                <key column="id"/>
                <many-to-one name="emailTemplate" column="email_template" class="model.message.email.EmailTemplate"/><!-- PROBLEM HERE -->
                <property name="contentId" column="content_id" type="string"/>
            </join>
        </subclass>
    </class>
</hibernate-mapping>

session.lock( emailTemplate, LockMode.NONE );
emailTemplate.getAttachments( ).size( ); // Init the lazy collection

select
   attachment0_.email_template as email12___, -- PROBLEM HERE
   attachment0_.id as id__,
   attachment0_.id as id0_,
   attachment0_.version as version4_0_,
   attachment0_.input as input4_0_,
   attachment0_.ssn as ssn4_0_,
   attachment0_.name as name4_0_,
   attachment0_.created as created4_0_,
   attachment0_.viewed as viewed4_0_,
   attachment0_.content_type as content9_4_0_,
   attachment0_.content_length as content10_4_0_,
   attachment0_.content as content4_0_,
   attachment0_1_.email_template as email2_6_0_,
   attachment0_1_.content_id as content3_6_0_
from document attachment0_
inner join attachment attachment0_1_
on attachment0_.id=attachment0_1_.id
where attachment0_.email_template=?