Modified exercise

Doc/Sda1/jpaintro.xml

@@ -361,63 +361,15 @@ CREATE TABLE `Lecture` (
                 <classname>de.hdm_stuttgart.mi.sda1.sql2catalog.model.Description</classname>.</para>
 
                 <tip>
-                  <orderedlist>
-                    <listitem>
-                      <para>Since <xref linkend="glo_JPA"/> requires an
-                      <code>@id</code> you must provide it. Though composite
-                      <code>@id</code>'s are possible you better define an
-                      additional (business) unique constraint by:</para>
-
-                      <programlisting language="none">@Table(
-	    uniqueConstraints=
-	        @UniqueConstraint(columnNames={"product", "orderIndex"})
-	)
-@Entity
-public class Description { ...</programlisting>
-                    </listitem>
-
-                    <listitem>
-                      <para>The required <code>@ManyToOne</code> annotation
-                      will result in a SQL schema property
-                      <property>product_id</property>. This may be renamed to
-                      <property>product</property> by adding
-                      <code>@JoinColumn(name="product")</code>.</para>
-                    </listitem>
-
-                    <listitem>
-                      <para>Adding @OneToMany(mappedBy = "product", <emphasis
-                      role="bold">cascade=CascadeType.ALL</emphasis>) allows
-                      for transitive persistence of dependent
-                      <classname>de.hdm_stuttgart.mi.sda1.sql2catalog.model.Description</classname>
-                      entities.</para>
-                    </listitem>
-                  </orderedlist>
+                  <para>Since <classname>Description</classname> instances are
+                  composites with respect to <classname>Product</classname>
+                  you might want to use @ElementCollection in favour of
+                  @ManyToOne / @OneToMany.</para>
                 </tip>
 
-                <para>A correct implementation should allow for enabling
-                <classname>rdbms2catalog.TestSchema</classname> by
-                uncommenting the test method's body. </para>
-              </listitem>
-
-              <listitem>
-                <para>Write a second <productname>Junit</productname> test
-                class checking for uniqueness of
-                (<property>product</property>,
-                <property>itemOrder</property>). Using duplicates should yield
-                an exception which may be accounted for by using:</para>
-
-                <programlisting language="none">public class TestSchemaConflict {
-...
-	@Test(expected= ...Exception.class)
-	public void insertData() {
-		{
-	          final EntityTransaction transaction = em.getTransaction();
-	          transaction.begin();
-	          
-	          final Product monkeyPickedTea = new Product(1, "Monkey Picked Tea", null);
-	          new Description(monkeyPickedTea, 0, "Picked only by specially trained monkeys");
-	          new Description(monkeyPickedTea, 0, "Rare wild Chinese tea"); // oops! Unique key violation
-...</programlisting>
+                <para>Test your implementation by uncommenting the test
+                method's body in
+                <classname>rdbms2catalog.TestSchema</classname>.</para>
               </listitem>
 
               <listitem>

P/Sda1/Jpa/rdbms2catalog/skeleton/src/test/java/rdbms2catalog/TestSchema.java

@@ -27,16 +27,13 @@ public class TestSchema {
 	          // accordingly the following commented code should work.
 	          
 //	          final Product monkeyPickedTea = new Product(1, "Monkey Picked Tea", null);
-//	          new Description(monkeyPickedTea, 0, "Picked only by specially trained monkeys");
-//	          new Description(monkeyPickedTea, 1, "Rare wild Chinese tea");
+//	          monkeyPickedTea.getDescriptions().add(new Description("Picked by specially trained monkeys"));
+//	          monkeyPickedTea.getDescriptions().add(new Description("Rare wild Chinese tea"));
 //	          
 //	          final Product instantTent = new Product(2, "4-Person Instant Tent", 15);
-//	          new Description(instantTent, 0, "Exclusive WeatherTec system.");
-//	          new Description(instantTent, 1, "4-person, 1-compartment tent");
-//	          new Description(instantTent, 2, "Pre-attached tent poles");
-//	          
-//	          em.persist(monkeyPickedTea);
-//	          em.persist(instantTent);
+//	          instantTent.getDescriptions().add(new Description("Exclusive WeatherTec system."));
+//	          instantTent.getDescriptions().add(new Description("4-person, 1-compartment tent"));
+//	          instantTent.getDescriptions().add(new Description("Pre-attached tent poles"));
 	          
 	          transaction.commit();
 	    }