Generated Mapping Files

Listing 4.9 shows the generated *.hbm.xml file for the Examresult class (the white space has been reformatted slightly to make it more readable). Note the two many-to-one associations; these are used in lieu of a Hibernate many-to-many relationship.

Listing 4.9. Generated Many-to-Many Examresult Class

<?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>
<!--
    Created by the Middlegen Hibernate plugin

    http://boss.bekk.no/boss/middlegen/
    http://hibernate.sourceforge.net/
-->

<class name="com.cascadetg.ch04.Examresult" table="examresult">

    <id name="id" type="java.lang.Long" column="ID">
        <generator class="native" />
    </id>

    <property name="score" type="int" column="score"
         length="11" />

    <!-- associations >
    <!-- bi-directional many-to-one association to Student -->
    <many-to-one name="student"
        class="com.cascadetg.ch04.Student"
        not-null="true">
        <column name="studentID" />
    </many-to-one>

    <!-- bi-directional many-to-one association to Exam -->
    <many-to-one name="exam" class="com.cascadetg.ch04.Exam"
        not-null="true" >
        <column name="examID" />
    </many-to-one>

</class>
</hibernate-mapping>

The flip side of the association with Examresult is shown in Listing 4.10 (again, the white space has been reformatted to make it more readable). The Exam mapping uses a set to manage the relationship. For more information on the set tag and the other nested portions of the mapping, see Chapter 5.

Listing 4.10. Generated Exam 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>
<!--
    Created by the Middlegen Hibernate plugin

    http://boss.bekk.no/boss/middlegen/
    http://hibernate.sourceforge.net/
-->

<class name="com.cascadetg.ch04.Exam" table="exam">

    <id name="id" type="java.lang.Long" column="ID" >
        <generator class="native" />
    </id>

    <property name="date" type="java.sql.Timestamp"
        column="date" length="14" />
    <property name="comment" type="java.lang.String"
        column="comment" length="255" />

    <!-- associations -->
    <!-- bi-directional many-to-one association to Course -->
    <many-to-one name="course"
        class="com.cascadetg.ch04.Course"
        not-null="true" >
        <column name="courseID" />
    </many-to-one>

    <!-- bi-directional one-to-many association to Examresult -->
    <set name="examresults" lazy="true" inverse="true" >
        <key>
            <column name="examID" />
        </key>
        <one-to-many class="com.cascadetg.ch04.Examresult" />
    </set>

</class>
</hibernate-mapping>

The mapping generated for the student table is shown in Listing 4.11 (extraneous white space removed).

Listing 4.11. Generated Student 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>
<!--
    Created by the Middlegen Hibernate plugin

    http://boss.bekk.no/boss/middlegen/
    http://hibernate.sourceforge.net/
-->

<class name="com.cascadetg.ch04.Student" table="student">

    <id name="id" type="java.lang.Long" column="ID" >
        <generator class="native" />
    </id>

    <property name="firstName" type="java.lang.String"
        column="firstName" length="100" />
    <property name="lastName" type="java.lang.String"
        column="lastName" length="100" />
    <property name="idString" type="java.lang.String"
        column="idString" length="20" />

    <!-- associations -->
    <!-- bi-directional one-to-many association to Examresult -->
    <set name="examresults" lazy="true" inverse="true">
        <key>
            <column name="studentID" />
        </key>
        <one-to-many class="com.cascadetg.ch04.Examresult" />
    </set>

</class>
</hibernate-mapping>

The mapping generated for the final table, course, is shown in Listing 4.12 (white space edited).

Listing 4.12. Generated Course 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>
<!--
    Created by the Middlegen Hibernate plugin

    http://boss.bekk.no/boss/middlegen/
    http://hibernate.sourceforge.net/
-->

<class name="com.cascadetg.ch04.Course" table="course" >

    <id name="id" type="java.lang.Long" column="ID" >
        <generator class="native" />
    </id>

    <property name="title" type="java.lang.String"
        column="title" length="100" />
    <property name="quarter" type="java.lang.String"
        column="quarter" length="4" />

    <!-- associations -->
    <!-- bi-directional one-to-many association to Exam -->
    <set name="exams" lazy="true" inverse="true" >
        <key>
            <column name="courseID" />
        </key>
        <one-to-many class="com.cascadetg.ch04.Exam"/>
    </set>

</class>
</hibernate-mapping>