Hibernate EntityManager クラス継承

InheritanceType：
JOINED
SINGLE_TABLE
TABLE_PER_CLASS

Project.java

package com.test;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;

@Entity
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class Project {
    private int projectId;
    private String projectName;

    @Id
    @GeneratedValue
    public int getProjectId() {
        return projectId;
    }

    public void setProjectId(int projectId) {
        this.projectId = projectId;
    }

    public String getProjectName() {
        return projectName;
    }

    public void setProjectName(String projectName) {
        this.projectName = projectName;
    }
}

Module.java

package com.test;

import javax.persistence.Entity;

@Entity
public class Module extends Project {
    private String moduleName;

    public String getModuleName() {
        return moduleName;
    }

    public void setModuleName(String moduleName) {
        this.moduleName = moduleName;
    }
}

Task.java

package com.test;

import javax.persistence.Entity;

@Entity
public class Task extends Module {
    private String tasknName;

    public String getTasknName() {
        return tasknName;
    }

    public void setTasknName(String tasknName) {
        this.tasknName = tasknName;
    }
}

ProjectTest.java

package com.test;

import static org.junit.Assert.*;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

import org.hibernate.engine.spi.EntityEntry;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

public class ProjectTest {

    static EntityManagerFactory entityManagerFactory;

    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
        entityManagerFactory = Persistence
                .createEntityManagerFactory("org.hibernate.tutorial.jpa");
    }

    @AfterClass
    public static void tearDownAfterClass() throws Exception {
        entityManagerFactory.close();
    }

    @Before
    public void setUp() throws Exception {
    }

    @After
    public void tearDown() throws Exception {
    }

    @Test
    public void test() {
        EntityManager entityManager = entityManagerFactory
                .createEntityManager();
        entityManager.getTransaction().begin();

        try {
            Project project = new Project();
            project.setProjectName("project1");

            Module module = new Module();
            module.setProjectName("project2");
            module.setModuleName("module1");

            Task task = new Task();
            task.setProjectName("project3");
            task.setModuleName("module3");
            task.setTasknName("task1");

            entityManager.persist(project);
            entityManager.persist(module);
            entityManager.persist(task);

            entityManager.getTransaction().commit();
        }
        catch (Exception e) {
            entityManager.getTransaction().rollback();
        }
    }
}

Project.sql

create table Project 
(
    projectId int4 not null, 
    projectName varchar(255), 
    primary key (projectId)
)

projectid	projectname
1	project1

Module.sql

create table Module 
(
    projectId int4 not null, 
    projectName varchar(255), 
    moduleName varchar(255), 
    primary key (projectId)
)

projectid	projectname	modulename
2	project2	module1

Task.sql

create table Task 
(
    projectId int4 not null, 
    projectName varchar(255), 
    moduleName varchar(255), 
    tasknName varchar(255), 
    primary key (projectId)
)

projectid	projectname	modulename	tasknname
3	project3	module3	task1