JPA_Tutorial_4_Assignments

Director <–> DVD

Right now the relationship between Director and DVD is one-way. Make it bidirectional.

Experiment with Inheritance Types

We use InheritanceType.JOINED. There are two others, SINGLE_TABLE, TABLE_PER_CLASS. Try out both of those and see if you can figure out what is happening for each of them. Be sure to re-run all the unit tests after switching to each type.

When you switch to the SINGLE_TABLE approach, what happens with column nullability, the isbn column (from Book), and the Dvd class?
When you switch to the TABLE_PER_CLASS approach, why does the key generation strategy have to change to in order fix the ‘Cannot use identity column key generation’ error? What did you change to, and why?
Can you sum up the advantages/disadvantages of each approach?

Sub-resource queries

Create a query that returns only Books or only Dvds.

Draw Tables

Create a visual representation of the database tables generated. Consider using SQuirreL SQL Client or the Quantum DB plugin for eclipse.

Update UI

Update your UI to allow a user to add a new DVD and a Patron to check out dvd’s.

Name Equality

During the first offering of the class, one student asked about the Name object, which is used in an equals() and hashCode() method. It turns out that the unit tests written did not expose the fact that the Name class lacks these methosd.

Here’s a unit test, add it and get it to work:

package entity;

import static org.junit.Assert.assertEquals;

import org.junit.Test;

public class NameTest {
    @Test
    public void nameSame() {
        final Name n1 = new Name("John", "Doe");
        final Name n2 = new Name("John", "Doe");

        assertEquals(n1, n2);
        assertEquals(n1.hashCode(), n2.hashCode());
    }
}