Hibernate ( Mapping – One-To-One ) Annotation Application

Hibernate ( Mapping – One-To-One ) Annotation Application

Hibernate ( Mapping – One-To-One ) Application

One-to-one relationship occurs when one entity is mapping exactly one occurrence in another entity.

A one-to-one relationship table design, a “stock” table contains exactly one record in “stockdetails” table.

Both tables have the same stockid as primary key.

In “stockdetails” table, stockid is the primary key and also a foreign key to STOCK table.

CREATE TABLE IF NOT EXISTS `stock` (

`stockid` int(11) NOT NULL,

`stockcode` varchar(50) NOT NULL,

`stockname` varchar(100) NOT NULL,

PRIMARY KEY (`stockid`),

UNIQUE KEY `stockcode` (`stockcode`,`stockname`)

)

CREATE TABLE IF NOT EXISTS `stockdetails` (

`stockid` int(11) NOT NULL,

`companyname` varchar(100) NOT NULL,

`companydesc` varchar(100) NOT NULL,

`remark` varchar(50) NOT NULL,

`listeddate` date NOT NULL,

PRIMARY KEY (`stockid`)

) ENGINE=InnoDB DEFAULT CHARSET=latin1;

ALTER TABLE `stockdetails`

ADD CONSTRAINT `stockdetails_ibfk_1` FOREIGN KEY (`stockid`) REFERENCES `stock` (`stockid`) ON DELETE CASCADE ON UPDATE CASCADE;

Step 1 - Create POJO (Model) classes ( Stock.java and StockDetails.java)

Step 2 - Hibernate Configurations ( hibernate.cfg.xml )

Step 3 - Create class to do the execution ( ExecuteApplication.java ) 

Step 1 - Create POJO classes 

 

Create POJO (Plain Old Java Object) classes that represents the Stock, and StockDetails.

package pojo;

import java.io.Serializable;

import javax.persistence.CascadeType;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.FetchType;

import javax.persistence.Id;

import javax.persistence.OneToOne;

import javax.persistence.Table;

import javax.persistence.UniqueConstraint;

@Entity

@Table( name = "stock", catalog = "myworkspace",

uniqueConstraints = {

@UniqueConstraint( columnNames = "stockcode" ),

@UniqueConstraint( columnNames = "stockname" )

})

public class Stock implements Serializable {

   /**

  *

  */

   private static final long serialVersionUID = 1L;

   @Id

   @Column(name = "stockid", unique = true, nullable = false)

   private Integer stockId;

   @Column(name = "stockcode", unique = true, nullable = false, length = 10)

   private String stockCode;

   @Column(name = "stockName", unique = true, nullable = false, length = 50)

   private String stockName;

   @OneToOne( fetch = FetchType.LAZY, mappedBy = "stock", cascade =   CascadeType.ALL)

   private StockDetails stockDetails;

   //TODO generate getters and setters

}

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package pojo;

import java.io.Serializable;

import java.util.Date;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.FetchType;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.OneToOne;

import javax.persistence.PrimaryKeyJoinColumn;

import javax.persistence.Table;

import org.hibernate.annotations.GenericGenerator;

import org.hibernate.annotations.Parameter;

@Entity

@Table (name = "stockdetails", catalog = "myworkspace")

public class StockDetails implements Serializable{

 

  /**

  *

  */

  private static final long serialVersionUID = 1L;

  

  @Id

  @GenericGenerator( name = "generator",

  strategy = "foreign",

  parameters = @Parameter ( name = "property", value = "stock"))

  @GeneratedValue( generator = "generator")

  @Column ( name = "stockid", unique = true, nullable = false)

  private Integer stockId;

 

  @Column ( name = "companyname", nullable = false)

  private String compName;

 

  @Column ( name = "companydesc", nullable = false)

  private String compDesc;

 

  @Column ( name = "remark", nullable = false)

  private String remark;

 

  @Column ( name = "listeddate", nullable = false)

  private Date listedDate;

 

  @OneToOne(fetch = FetchType.LAZY)

  @PrimaryKeyJoinColumn

  private Stock stock;

  //TODO generate getters and setters

}

Step 2 - Hibernate Configurations

Create configuration file name as hibernate.cfg.xml and save it.

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE hibernate-configuration PUBLIC

   "-//Hibernate/Hibernate Configuration DTD 3.0//EN"

   "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

    

   <hibernate-configuration>

        <session-factory>

          <!-- SQL dialect -->

          <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

          <!-- Database connection settings -->

          <property name="hibernate.connection.url">jdbc:mysql://localhost:3306 /myworkspace</property>

          <property name="hibernate.connection.username">root</property>

          <property name="hibernate.connection.password">res13pg</property>

          <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>

          <!-- JDBC connection pool (use the built-in) -->

        <property name="connection.pool_size">1</property>

          <!-- Echo all executed SQL to stdout -->

          <property name="show_sql">true</property>

 

          <mapping class="pojo.Stock"/>

          <mapping class="pojo.StockDetails"/>

        </session-factory>

    </hibernate-configuration>

 

Step 3 - Create Execute class

Create a ExecuteApplication class to do the execution.

package impl;

import java.util.Date;

import java.util.Iterator;

import java.util.List;

import org.hibernate.Session;

import org.hibernate.Transaction;

import org.hibernate.cfg.AnnotationConfiguration;

import pojo.Stock;

import pojo.StockDetails;

public class ExecuteApplication {

   /**

   * @param args

   */

   public static void main(String[] args) {

      ExecuteApplication executeEmployee = new ExecuteApplication();

      executeEmployee.addStock();

      executeEmployee.listStocks();

   }

   private void addStock(){

      Transaction transaction = null;

      Session hbSession = new     AnnotationConfiguration().configure("config/hibernate.cfg.xml")

 .buildSessionFactory().openSession();

 

      try{

          transaction = hbSession.beginTransaction();

    

          Stock stock = new Stock();

          stock.setStockId(123456);

          stock.setStockCode("NB100");

          stock.setStockName("Notebooks");

          StockDetails stockDetails = new StockDetails();

          stockDetails.setCompName("Abans");

          stockDetails.setCompDesc("Pionior in Notebooks");

          stockDetails.setRemark("Good Service");

          stockDetails.setListedDate(new Date());

          stock.setStockDetails(stockDetails);

          stockDetails.setStock(stock);

          hbSession.save(stock);

          hbSession.getTransaction().commit();

          System.out.println("Insert the Stock Record");

      }catch (Exception e) {

          if(null != transaction){

              transaction.rollback();

          }

          e.printStackTrace();

      }finally{

          hbSession.flush();

          hbSession.close();

      }

  }

  private void listStocks(){

        Transaction transaction = null;

        Session hbSession = new AnnotationConfiguration().configure("config/hibernate.cfg.xml")

.buildSessionFactory().openSession();

         try{

             transaction = hbSession.beginTransaction();

             @SuppressWarnings("unchecked")

             List<Stock> stockList = hbSession.createQuery("FROM Stock").list();

              

             for(Iterator<Stock> iterator = stockList.iterator(); iterator.hasNext();){

                   Stock stock = iterator.next();

                   System.out.println("");

                   System.out.println("StockId : " + stock.getStockId());

                   System.out.println("StockCode : " + stock.getStockCode());

                   System.out.println("StockName : " + stock.getStockName());

                   System.out.println("CompanyName : " +  stock.getStockDetails().getCompName());

                   System.out.println("CompanyDesc : " + stock.getStockDetails().getCompDesc());

                   System.out.println("Remark : " + stock.getStockDetails().getRemark());

                   System.out.println("ListedDate : " + stock.getStockDetails().getListedDate());

              }

              hbSession.getTransaction().commit();

         }catch (Exception e) {

               if(null != transaction){

                     transaction.rollback();

               }

               e.printStackTrace();

          }finally{

               hbSession.flush();

               hbSession.close();

          }

     }

}

 

Out put on the above application as follows.