Java Tutorial/Hibernate/Primary Key

Composed ID

File: AccAcc.java

import java.io.*;
public class AccAcc implements Serializable { 
  private String id; 
  private int accountnum; 
  private String acctype; 
  private String name;
  public AccAcc() {
  }
  public AccAcc(int i, String t, String n) {
    accountnum = i;
    acctype = t;
    name = n;
  }
  public void setId(String s) {
    id = s;
  }
  public String getId() {
    return id;
  }
  public void setAccountnum(int i) {
    accountnum = i;
  }
  public int getAccountnum() {
    return accountnum;
  }  
  public void setAcctype(String s) {
    acctype = s;
  }
  public String getAcctype() {
    return acctype;
  }
  public void setname(String s) {
    name = s;
  }
  public String getName() {
    return name;
  }
    public boolean equals(Object obj) {
        if (obj == null) return false;
        if (!this.getClass().equals(obj.getClass())) return false;
        
        AccAcc obj2 = (AccAcc)obj;
        if (this.id.equals(obj2.getId()) &&
            this.accountnum == obj2.getAccountnum() &&
            this.acctype.equals(obj2.getAcctype()) &&
            this.name.equals(obj2.getName())) {
            return true;
        }
        
    return false;
    }
    public int hashCode() {      
        int tmp = 0;
        // Method 1-Concatenate the strings
        tmp = (id + accountnum + name + acctype).hashCode();
        return tmp;
    }
}

Use Int As ID which starts from 0

File: Main.java

import java.util.Date;
import org.hibernate.Session;
public class Main {
  public static void main(String[] args) throws Exception {
    HibernateUtil hibernateUtil = new HibernateUtil();
    hibernateUtil.executeSQLCommand("create table survey (id int,name varchar, purchasedate date);");
    Session session = hibernateUtil.getSession();
    Survey survey = new Survey();
    survey.setName("Survey");
    survey.setPurchaseDate(new Date());
    System.out.println(survey.getId());
    
    session.save(survey);
    session.flush();
    
    System.out.println(survey.getId());
    Survey surveyInSession = (Survey) session.get(Survey.class, survey.getId());
    System.out.println(surveyInSession.getName());
    session.close();
    hibernateUtil.checkData("select * from survey");
  }
}

Use Long AS ID

File: Main.java

import java.util.Date;
import org.hibernate.Session;
public class Main {
  public static void main(String[] args) throws Exception {
    HibernateUtil hibernateUtil = new HibernateUtil();
    hibernateUtil.executeSQLCommand("create table survey (id int,name varchar, purchasedate date);");
    Session session = hibernateUtil.getSession();
    Survey survey = new Survey();
    survey.setName("Survey");
    survey.setPurchaseDate(new Date());
    System.out.println(survey.getId());
    
    session.save(survey);
    session.flush();
    
    System.out.println(survey.getId());
    Survey surveyInSession = (Survey) session.get(Survey.class, survey.getId());
    System.out.println(surveyInSession.getName());
    session.close();
    hibernateUtil.checkData("select * from survey");
  }
}

UUID HEX as Primary Key

File: Main.java

import java.util.Date;
import java.util.List;
import org.hibernate.Query;
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))");
    Session session = hibernateUtil.getSession();
    CD cd = new CD();
    
    session.save(cd);
    session.flush();
    session.close();
    hibernateUtil.checkData("select * from CD");
  }
}