Java Tutorial/Hibernate/Mapping Inheritance

Class In Hierarchy Has Its Own Table

File: Main.java

import java.util.Iterator;
import java.util.List;
import org.hibernate.Session;
public class Main {
  public static void main(String[] args) throws Exception {
    HibernateUtil hibernateUtil = new HibernateUtil();
    hibernateUtil
        .executeSQLCommand("create table CD(id varchar,title varchar,artist varchar,purchaseDate date,cost decimal(6,2))");
    hibernateUtil
    .executeSQLCommand("create table SECD(id varchar,title varchar,artist varchar,purchaseDate date,cost decimal(6,2), newfeatures varchar)");
    hibernateUtil
    .executeSQLCommand("create table ICD(id varchar,title varchar,artist varchar,purchaseDate date,cost decimal(6,2),languages varchar, region int)");
    Session session = hibernateUtil.getSession();
    CD cd = new CD();
    cd.setArtist("artist");
    cd.setTitle("title");
    
    String id = (String)session.save(cd);
    System.out.println(id);
    
    SpecialEditionCD scd = new SpecialEditionCD();
    scd.setNewfeatures("new");
    session.save(scd);
    
    InternationalCD icd = new InternationalCD();
    icd.setLanguages("ENG");
    session.save(icd);
    
    session.flush();
    List cds = session.createQuery("from CD").list();
    Iterator iter = cds.iterator();
    while (iter.hasNext()) {
      CD cd1 = (CD) iter.next();
      System.out.println(cd1.getArtist());
    }
    session.close();
    hibernateUtil.checkData("select * from CD");
    hibernateUtil.checkData("select * from SECD");
    hibernateUtil.checkData("select * from ICD");
  }
}

Class In Hierarchy Maps To One Table

File: Main.java

import java.util.Iterator;
import java.util.List;
import org.hibernate.Session;
public class Main {
  public static void main(String[] args) throws Exception {
    HibernateUtil hibernateUtil = new HibernateUtil();
    hibernateUtil
        .executeSQLCommand("create table CD(id varchar,title varchar,artist varchar,purchaseDate date,cost decimal(6,2),languages varchar, newfeatures varchar)");

    Session session = hibernateUtil.getSession();
    CD cd = new CD();
    cd.setArtist("artist");
    cd.setTitle("title");
    
    String id = (String)session.save(cd);
    System.out.println(id);
    
    SpecialEditionCD scd = new SpecialEditionCD();
    scd.setNewfeatures("new");
    session.save(scd);
    
    InternationalCD icd = new InternationalCD();
    icd.setLanguages("ENG");
    session.save(icd);
    
    session.flush();
    session.close();
    hibernateUtil.checkData("select * from CD");
  }
}

Mapping Class Hierarchy

File: Main.java

import org.hibernate.Session;
public class Main {
  public static void main(String[] args) throws Exception {
    HibernateUtil hibernateUtil = new HibernateUtil();
    hibernateUtil
        .executeSQLCommand("create table Product(id int, name varchar, description varchar, price decimal(6,2), supplierid int)");
     
    hibernateUtil
    .executeSQLCommand("create table Supplier (id int , name varchar)");
    hibernateUtil
    .executeSQLCommand("create table Software(id int, name varchar, description varchar, price decimal(6,2), supplierid int, version varchar)");
    
    Session session = hibernateUtil.getSession();
    Supplier superCorp = new Supplier();
    superCorp.setName("Supplier1");
    session.save(superCorp);
    
    Supplier megaInc = new Supplier();
    megaInc.setName("Supplier2");
    session.save(megaInc);        
    Product mouse = new Product("Product1","first product", 20.0);
    mouse.setSupplier(superCorp);
    superCorp.getProducts().add(mouse);
    session.flush();
    Product mouse2 = new Product("Product2","second product", 22.0);
    mouse2.setSupplier(superCorp);
    superCorp.getProducts().add(mouse2);        
    
    Product keyboard = new Product("Product3", "third product", 30.0);
    keyboard.setSupplier(megaInc);
    megaInc.getProducts().add(keyboard);
    Software webBrowser = new Software("Web Browser","new browser", 75.0, "2.0");
    webBrowser.setSupplier(superCorp);
    superCorp.getProducts().add(webBrowser);
    Software email = new Software("Email","email client", 49.99, "4.1 Edition");
    email.setSupplier(megaInc);
    megaInc.getProducts().add(email);    
    session.flush();
    session.close();
    hibernateUtil.checkData("select * from Product");
    hibernateUtil.checkData("select * from Software");
    hibernateUtil.checkData("select * from Supplier");
  }
}