Hibernate實作Table per subclass之例子

testPerSubClass Table per subclass :每個子類別對應一張表，並與主類別共用主表




1.建立表格：





drop table if exists t_dvd02;

drop table if exists t_book02;

drop table if exists t_item02;




create table t_item02(

id int(11) auto_increment,

name varchar(30) default '',

manufacture varchar(50) default '',

primary key(id));




create table t_book02(

id int(11),

pagecount int(4),

primary key(id),

foreign key(id) references t_item02(id));




create table t_dvd02(

id int(11),

regioncode varchar(30),

primary key(id),

foreign key(id) references t_item02(id));













2.建立TItem02.hbm.xml及TBook02.hbm.xml及TDvd02.hbm.xml：


<?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

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

<!-- Generated 2009/8/7 ?W?? 11:20:42 by Hibernate Tools 3.2.4.GA -->

<hibernate-mapping>

    <class name="org.redsaga.quickstart.TItem02" table="t_item02" catalog="manning">

        <id name="id" type="java.lang.Integer">

            <column name="id" />

            <generator class="identity" />

        </id>

        <property name="name" type="string">

            <column name="name" length="30" />

        </property>

        <property name="manufacture" type="string">

            <column name="manufacture" length="50" />

        </property>

        <joined-subclass name="org.redsaga.quickstart.TDvd02" table="t_dvd02">

 <key column="id"/>

 <property name="regioncode" column="regioncode" type="string"/>

        </joined-subclass>

        <joined-subclass name="org.redsaga.quickstart.TBook02" table="t_book02">

 <key column="id"/>

 <property name="pagecount" column="pagecount" type="java.lang.Integer"></property>

        </joined-subclass>

     </class>

</hibernate-mapping>

====================================





<?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

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

<!-- Generated 2009/8/7 ?W?? 11:20:42 by Hibernate Tools 3.2.4.GA -->

<hibernate-mapping>

    <class name="org.redsaga.quickstart.TBook02" table="t_book02" catalog="manning">

        <id name="id" type="int">

            <column name="id" />

            <generator class="foreign">

                <param name="property">TItem02</param>

            </generator>

        </id>

        <one-to-one name="TItem02" class="org.redsaga.quickstart.TItem02" constrained="true"></one-to-one>

        <property name="pagecount" type="java.lang.Integer">

            <column name="pagecount" />

        </property>

    </class>

</hibernate-mapping>

======================================





<?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

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

<!-- Generated 2009/8/7 ?W?? 11:20:42 by Hibernate Tools 3.2.4.GA -->

<hibernate-mapping>

    <class name="org.redsaga.quickstart.TDvd02" table="t_dvd02" catalog="manning">

        <id name="id" type="int">

            <column name="id" />

            <generator class="foreign">

                <param name="property">TItem02</param>

            </generator>

        </id>

        <one-to-one name="TItem02" class="org.redsaga.quickstart.TItem02" constrained="true"></one-to-one>

        <property name="regioncode" type="string">

            <column name="regioncode" length="30" />

        </property>

    </class>

</hibernate-mapping>

======================================




3.建立TItem02.java及TBook02.java及TDvd02.java：


package org.redsaga.quickstart;




// Generated 2009/8/7 上午 11:20:42 by Hibernate Tools 3.2.4.GA




/**

 * TItem02 generated by hbm2java

 */

public class TItem02 implements java.io.Serializable {




 private Integer id;

 private String name;

 private String manufacture;




 public TItem02() {

 }




 public TItem02(String name, String manufacture) {

  this.name = name;

  this.manufacture = manufacture;

 }




 public Integer getId() {

  return this.id;

 }




 public void setId(Integer id) {

  this.id = id;

 }




 public String getName() {

  return this.name;

 }




 public void setName(String name) {

  this.name = name;

 }




 public String getManufacture() {

  return this.manufacture;

 }




 public void setManufacture(String manufacture) {

  this.manufacture = manufacture;

 }

}

===================================





package org.redsaga.quickstart;




// Generated 2009/8/7 上午 11:20:42 by Hibernate Tools 3.2.4.GA




/**

 * TBook02 generated by hbm2java

 */

public class TBook02 extends TItem02 implements java.io.Serializable {




 private Integer pagecount;




 public TBook02() {

 }




 public TBook02(Integer pagecount) {

  this.pagecount = pagecount;

 }




 public Integer getPagecount() {

  return this.pagecount;

 }




 public void setPagecount(Integer pagecount) {

  this.pagecount = pagecount;

 }




}

===================================





package org.redsaga.quickstart;




// Generated 2009/8/7 上午 11:20:42 by Hibernate Tools 3.2.4.GA




/**

 * TDvd02 generated by hbm2java

 */

public class TDvd02 extends TItem02 implements java.io.Serializable {




 private int id;

 private String regioncode;




 public TDvd02() {

 }




 public TDvd02(String regioncode) {

  this.regioncode = regioncode;

 }




 public String getRegioncode() {

  return this.regioncode;

 }




 public void setRegioncode(String regioncode) {

  this.regioncode = regioncode;

 }




}

====================================







4.建立JUnit測試Method(testPerSubClass)：


 /**

  * testPerSubClass Table per subclass 每個子類別對應一張表，並與主類別共用主表

  * @throws Exception

  */

 public void testPerSubClass() throws Exception {

  Transaction tran = null;

  TBook02 book = new TBook02();

  TDvd02 dvd = new TDvd02();

  book.setName("倚天屠龍記");

  book.setManufacture("金庸");

  book.setPagecount(288);

  dvd.setName("今天不回家");

  dvd.setManufacture("全家");

  dvd.setRegioncode("亞洲");

  try{

   tran = session.beginTransaction();

   session.save(book);

   session.save(dvd);

   session.flush();

   tran.commit();

   


   List list = session.createQuery(" from TItem02").list();

   Iterator it = list.iterator();

   while(it.hasNext()){

    TItem02 item = (TItem02)it.next();

    System.out.println(item.getId()+","+item.getName()+","+item.getManufacture());

   }

   


  }catch(HibernateException e){

   e.printStackTrace();

  }

 }

==================================








5.測試結果：

MySql結果：




console結果：




Hibernate: insert into manning.t_item02 (name, manufacture) values (?, ?)

Hibernate: insert into t_book02 (pagecount, id) values (?, ?)

Hibernate: insert into manning.t_item02 (name, manufacture) values (?, ?)

Hibernate: insert into t_dvd02 (regioncode, id) values (?, ?)

Hibernate: select titem02x0_.id as id5_, titem02x0_.name as name5_, titem02x0_.manufacture as manufact3_5_, titem02x0_1_.regioncode as regioncode6_, titem02x0_2_.pagecount as pagecount7_, case when titem02x0_1_.id is not null then 1 when titem02x0_2_.id is not null then 2 when titem02x0_.id is not null then 0 end as clazz_ from manning.t_item02 titem02x0_ left outer join t_dvd02 titem02x0_1_ on titem02x0_.id=titem02x0_1_.id left outer join t_book02 titem02x0_2_ on titem02x0_.id=titem02x0_2_.id

1,倚天屠龍記,金庸

2,今天不回家,全家