diff --git a/Doc/course.xml b/Doc/course.xml
index 6ff75c0931366b126f26757d2ef6f07d97c15200..53a3ce0097b20467e59081a4aaf0c8946b889115 100644
--- a/Doc/course.xml
+++ b/Doc/course.xml
@@ -18011,7 +18011,7 @@ CREATE TABLE BankAccount (
</chapter>
<chapter xml:id="mappingRelatedEntities">
- <title>Mapping related entities</title>
+ <title>Mapping related Components and entities</title>
<section xml:id="primaryKeyRevisit">
<title>Primary keys revisited</title>
@@ -18768,8 +18768,8 @@ public class Persist {
</orderedlist>
<para>After successfully inserting these three entities
- <personname>Eve Blix</personname> may no longer be entitled to use her
- laptop. We decouple these two entities:</para>
+ <personname>Eve Blix</personname> shall no longer be entitled to use
+ her laptop. We thus decouple these two entities:</para>
<programlisting>package entity.company2;
public class LoadAndDeRegister {
@@ -18783,6 +18783,27 @@ public class LoadAndDeRegister {
<para>All three entities are still present in our database but the
corresponding foreign key has been set to <code>NULL</code>.</para>
+
+ <qandaset role="exercise">
+ <title>One laptop per employee</title>
+
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Consider a company where each employee must have a
+ laptop being assigned and modify the mapping in
+ <classname>entity.company2.Employee</classname>
+ accordingly.</para>
+ </question>
+
+ <answer>
+ <para>See <emphasis
+ role="bold">@OneToOne(optional=false,...</emphasis> in
+ <classname>entity.company3.Employee</classname>.</para>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
</section>
</chapter>
</part>
diff --git a/ws/eclipse/HibIntro/src/main/java/entity/company3/Employee.java b/ws/eclipse/HibIntro/src/main/java/entity/company3/Employee.java
new file mode 100644
index 0000000000000000000000000000000000000000..c7bd76914fe7c6378b1f5f0b45a8287915764cbb
--- /dev/null
+++ b/ws/eclipse/HibIntro/src/main/java/entity/company3/Employee.java
@@ -0,0 +1,71 @@
+package entity.company3;
+
+import javax.persistence.CascadeType;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.OneToOne;
+import javax.persistence.Table;
+import javax.persistence.UniqueConstraint;
+
+/**
+ *
+ * {@link Employee} instances related to {@link Department}
+ *
+ */
+@Entity
+@Table(uniqueConstraints={@UniqueConstraint(columnNames={"staffNumber"})})
+public class Employee {
+
+ @Id
+ @GeneratedValue
+ public Long getId() {return id;}
+ protected void setId(Long id) {this.id = id;}
+ private Long id;
+
+ public int getStaffNumber() { return staffNumber;}
+ public void setStaffNumber(int staffNumber) { this.staffNumber = staffNumber;}
+ int staffNumber = Integer.MIN_VALUE;
+
+ public String getCname() { return cname;}
+ public void setCname(String cname) { this.cname = cname;}
+ private String cname; // Common name
+
+ /**
+ * One laptop per {@link Employee}.
+ *
+ * @return Laptop "owned" by {@link Employee}.
+ */
+ @OneToOne(optional=false, cascade={CascadeType.ALL})
+ public Laptop getLaptop() { return laptop;}
+ public void setLaptop(Laptop laptop) {this.laptop = laptop;}
+ private Laptop laptop;// Workstation for employees.
+
+ protected Employee(){}
+
+ public Employee(final int staffNumber, final String cname) {
+ setStaffNumber(staffNumber);
+ setCname(cname);
+ }
+ @Override
+ public boolean equals(Object other) {
+ if (this == other) {
+ return true;
+ } else if (Integer.MIN_VALUE == getStaffNumber()) {
+ return false;
+ } else if (other instanceof Employee) {
+ final Employee that = (Employee) other;
+ return this.getStaffNumber() == that.getStaffNumber();
+ } else {
+ return false;
+ }
+ }
+ @Override
+ public int hashCode() {
+ if (Integer.MIN_VALUE == getStaffNumber()) {
+ return System.identityHashCode(this);
+ } else {
+ return getStaffNumber();
+ }
+ }
+}
\ No newline at end of file
diff --git a/ws/eclipse/HibIntro/src/main/java/entity/company3/Laptop.java b/ws/eclipse/HibIntro/src/main/java/entity/company3/Laptop.java
new file mode 100644
index 0000000000000000000000000000000000000000..c53d327d4665542f9aaacc47b7d87fc331d643e5
--- /dev/null
+++ b/ws/eclipse/HibIntro/src/main/java/entity/company3/Laptop.java
@@ -0,0 +1,57 @@
+package entity.company3;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.Table;
+import javax.persistence.UniqueConstraint;
+
+/**
+ *
+ * Laptops possibly being assigned to {@link Employee}
+ *
+ */
+@Entity
+@Table(uniqueConstraints={@UniqueConstraint(columnNames={"idNumber"})})
+public class Laptop {
+
+ @Id
+ @GeneratedValue
+ public Long getId() {return id;}
+ protected void setId(Long id) {this.id = id;}
+ private Long id;
+
+ /**
+ * @return The device's unique part number
+ */
+ public int getIdNumber() { return idNumber;}
+ public void setIdNumber(int idNumber) { this.idNumber = idNumber;}
+ int idNumber;
+
+ protected Laptop(){}
+
+ public Laptop(final int idNumber) {
+ setIdNumber(idNumber);
+ }
+ @Override
+ public boolean equals(Object other) {
+ if (this == other) {
+ return true;
+ } else if (Integer.MIN_VALUE == getIdNumber()) {
+ return false;
+ } else if (other instanceof Laptop) {
+ final Laptop that = (Laptop) other;
+ return this.getIdNumber() == that.getIdNumber();
+ } else {
+ return false;
+ }
+ }
+ @Override
+ public int hashCode() {
+ if (Integer.MIN_VALUE == getIdNumber()) {
+ return System.identityHashCode(this);
+ } else {
+ return getIdNumber();
+ }
+ }
+}
\ No newline at end of file
diff --git a/ws/eclipse/HibIntro/src/main/java/entity/company3/LoadAndDeRegister.java b/ws/eclipse/HibIntro/src/main/java/entity/company3/LoadAndDeRegister.java
new file mode 100644
index 0000000000000000000000000000000000000000..55e3deff4b701a34b6d849856016101c6a868575
--- /dev/null
+++ b/ws/eclipse/HibIntro/src/main/java/entity/company3/LoadAndDeRegister.java
@@ -0,0 +1,26 @@
+package entity.company3;
+
+import hibintro.util.HibernateUtil;
+
+import org.hibernate.Session;
+import org.hibernate.Transaction;
+
+/**
+ * Removing {@link Laptop} from {@link Employee}
+ */
+public class LoadAndDeRegister {
+ /**
+ * @param args not used.
+ */
+ public static void main(String[] args) {
+ final Session session = HibernateUtil.createSessionFactory("entity/company2/hibernate.cfg.xml").openSession();
+ {
+ final Transaction transaction = session.beginTransaction();
+ final Employee eve = (Employee) session.load(Employee.class, 2L);
+
+ eve.setLaptop(null);
+
+ transaction.commit();
+ }
+ }
+}
\ No newline at end of file
diff --git a/ws/eclipse/HibIntro/src/main/java/entity/company3/Persist.java b/ws/eclipse/HibIntro/src/main/java/entity/company3/Persist.java
new file mode 100644
index 0000000000000000000000000000000000000000..e4a3e1f89b5b64ebfdbbb7288b048a9ee021039b
--- /dev/null
+++ b/ws/eclipse/HibIntro/src/main/java/entity/company3/Persist.java
@@ -0,0 +1,33 @@
+package entity.company3;
+
+import hibintro.util.HibernateUtil;
+
+import org.hibernate.Session;
+import org.hibernate.Transaction;
+
+/**
+ * Persisting {@link Employee} possibly along with
+ * personal assigned laptops.
+ */
+public class Persist {
+ /**
+ * @param args not used.
+ */
+ public static void main(String[] args) {
+ final Session session = HibernateUtil.createSessionFactory("entity/company3/hibernate.cfg.xml").openSession();
+ {
+ final Transaction transaction = session.beginTransaction();
+ final Employee martin = new Employee(123, "Martin Goik"),
+ eve = new Employee(140, "Eve Blix");
+
+ final Laptop superCoolGadget = new Laptop(2213);
+ eve.setLaptop(superCoolGadget);
+ // Now only save the employee transients,
+ // superCoolGadget will be saved automatically due to
+ // CascadeType.ALL
+ session.save(martin);
+ session.save(eve);
+ transaction.commit();
+ }
+ }
+}
\ No newline at end of file
diff --git a/ws/eclipse/HibIntro/src/main/java/entity/company3/hibernate.cfg.xml b/ws/eclipse/HibIntro/src/main/java/entity/company3/hibernate.cfg.xml
new file mode 100644
index 0000000000000000000000000000000000000000..78e99b2113fee9c8bace82bd96e1d9f2046a2aeb
--- /dev/null
+++ b/ws/eclipse/HibIntro/src/main/java/entity/company3/hibernate.cfg.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!DOCTYPE hibernate-configuration PUBLIC
+ "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
+ "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
+
+<hibernate-configuration>
+ <session-factory >
+ <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
+ <property name="hibernate.connection.password">XYZ</property>
+ <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hdm</property>
+ <property name="hibernate.connection.username">hdmuser</property>
+ <property name="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
+ <property name="hibernate.show_sql">false</property>
+ <property name="hibernate.format_sql">true</property>
+ <property name="hibernate.hbm2ddl.auto">update</property>
+
+ <mapping class="entity.company3.Laptop"/>
+ <mapping class="entity.company3.Employee"/>
+ </session-factory>
+</hibernate-configuration>