hibernate - 同样，JoinTable 未填充多对多 hibernate 关系

Question

|AA|多对多|BB|多对多 |CC|

与连接表映射成为

|AA|--|AA_BB|--|BB|--|BB_CC|--|CC|

(抱歉，我无法发布图片，声誉低)

编辑:简短的问题是为什么如果a创建Aa元素，Bb元素，Cc元素将 Cc 添加到 Bb 集合，将 Bb 添加到 Aa 集合保存(Aa)工作正常(AA_BB 已填充)？

但是如果我创建一个 Bb 元素、Aa 元素、Cc 元素将 Aa 添加到 Bb 集合中将抄送添加到 Bb 收藏保存(Bb)(AA_BB未填写？)

BB_CC 始终已满。

结束编辑

 CREATE TABLE BB_CC (
  BBIDBB number(10) NOT NULL, 
  CCIDCC number(10) NOT NULL, 
  PRIMARY KEY (BBIDBB, 
  CCIDCC));
CREATE TABLE AA_BB (
  AAIDAA number(10) NOT NULL, 
  BBIDBB number(10) NOT NULL, 
  PRIMARY KEY (AAIDAA, 
  BBIDBB));
CREATE TABLE CC (
  IDCC  number(10) NOT NULL, 
  DESCR varchar2(10) NOT NULL, 
  PRIMARY KEY (IDCC));
CREATE TABLE BB (
  IDBB  number(10) NOT NULL, 
  DESCR varchar2(10) NOT NULL, 
  PRIMARY KEY (IDBB));
CREATE TABLE AA (
  IDAA  number(10) NOT NULL, 
  DESCR varchar2(10) NOT NULL, 
  PRIMARY KEY (IDAA));
ALTER TABLE BB_CC ADD CONSTRAINT FKBB_CC976918 FOREIGN KEY (BBIDBB) REFERENCES BB (IDBB);
ALTER TABLE BB_CC ADD CONSTRAINT FKBB_CC529716 FOREIGN KEY (CCIDCC) REFERENCES CC (IDCC);
ALTER TABLE AA_BB ADD CONSTRAINT FKAA_BB470776 FOREIGN KEY (AAIDAA) REFERENCES AA (IDAA);
ALTER TABLE AA_BB ADD CONSTRAINT FKAA_BB23574 FOREIGN KEY (BBIDBB) REFERENCES BB (IDBB);

hibernate 配置文件

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
<!--  ORACLE -->
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="connection.url">jdbc:oracle:thin:@10.10.1.8:1521:GEROS</property>
        <property name="connection.username">xxxx</property>
        <property name="connection.password">xxxx</property>
        <property name="dialect">org.hibernate.dialect.OracleDialect</property>

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">1</property>

        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>

        <!-- Drop and re-create the database schema on startup-->
        <property name="hbm2ddl.auto">create</property>

        <!-- Names the annotated entity class -->
        <mapping class="it.erreeffe.erreeffe2.Aa"/>
        <mapping class="it.erreeffe.erreeffe2.Bb"/>
        <mapping class="it.erreeffe.erreeffe2.Cc"/>
    </session-factory>
</hibernate-configuration>

以及表中的反向 jpa 类Aa(Bb、Cc 类似)缺少一些部分。

@Entity
public class Aa implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @SequenceGenerator(name="AA_IDAA_GENERATOR", sequenceName="SEQ_AA")
    @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="AA_IDAA_GENERATOR")
    private long idaa;

    private String descr;

    //bi-directional many-to-many association to Bb
    @ManyToMany(cascade={CascadeType.ALL})
    @JoinTable(
        name="AA_BB"
        , joinColumns={
            @JoinColumn(name="AAIDAA")
            }
        , inverseJoinColumns={
            @JoinColumn(name="BBIDBB")
            }
        )
    private Set<Bb> bbs;

我的测试，第一个有效，第二个无效。

第一:

Session session;
        SessionFactory sf_ORA = new Configuration().configure(
                "hibernate.cfg.ora.xml").buildSessionFactory();
        session = sf_ORA.openSession();

//A
        Aa a = new Aa();
        a.setDescr("A1");
        a.setBbs(new HashSet<Bb>());
        //B
        Bb b1 = new Bb();
        b1.setCcs(new HashSet<Cc>());
        Bb b2 =new Bb();
        b2.setCcs(new HashSet<Cc>());
        b1.setDescr("B1");
        b2.setDescr("B2");
        //C
        Cc c1 = new Cc();
        Cc c2 = new Cc();
        Cc c3 = new Cc();
        c1.setDescr("C1");
        c2.setDescr("C2");
        c3.setDescr("C3");
        //FILL B
        b1.getCcs().add(c1);
        b1.getCcs().add(c2);
        b2.getCcs().add(c2);
        b2.getCcs().add(c3);
        //FILL A
        a.getBbs().add(b1);
        a.getBbs().add(b2);

session.beginTransaction();
        try
        {
            session.save(a);
            session.flush();
            session.getTransaction().commit();
        }
        catch(HibernateException ex)
        {
            session.getTransaction().rollback();
            throw ex;
        }

这做正确的工作:Hibernate 为我创建了所有需要的语句:

Hibernate: insert into Aa (descr, idaa) values (?, ?)
Hibernate: insert into Bb (descr, idbb) values (?, ?)
Hibernate: insert into Cc (descr, idcc) values (?, ?)
Hibernate: insert into Cc (descr, idcc) values (?, ?)
Hibernate: insert into Bb (descr, idbb) values (?, ?)
Hibernate: insert into Cc (descr, idcc) values (?, ?)
Hibernate: insert into AA_BB (AAIDAA, BBIDBB) values (?, ?)
Hibernate: insert into AA_BB (AAIDAA, BBIDBB) values (?, ?)
Hibernate: insert into BB_CC (BBIDBB, CCIDCC) values (?, ?)
Hibernate: insert into BB_CC (BBIDBB, CCIDCC) values (?, ?)
Hibernate: insert into BB_CC (BBIDBB, CCIDCC) values (?, ?)
Hibernate: insert into BB_CC (BBIDBB, CCIDCC) values (?, ?)

连接结果查询是正确的:

A1|B1|C1

A1|B1|C2

A1|B2|C2

A1|B2|C3

第二(Ta-dan 这就是问题所在)从DB读取B1，添加新的Aa(A2)到B1。Aas集合添加新的Cc(c4)到B1。Ccs集合，更新B1。

Bb b1=null;
        session.beginTransaction();
        try
        {
            Query qGetB1=session.createQuery("Select id from Bb where DESCR ='B1'" );
            long idB1=(Long) qGetB1.list().get(0);
            b1=(Bb) session.load(Bb.class, idB1);
            session.flush();
            session.getTransaction().commit();
        }
        catch(HibernateException ex)
        {
            session.getTransaction().rollback();
            throw ex;
        }

        Aa a2 = new Aa();
        a2.setDescr("A2");
        Cc c4 = new Cc();
        c4.setDescr("C4");

        b1.getAas().add(a2);
        b1.getCcs().add(c4);


        session.beginTransaction();
        try
        {
            session.flush();
            session.saveOrUpdate(b1);
            session.flush();
            session.getTransaction().commit();
        }
        catch(HibernateException ex)
        {
            session.getTransaction().rollback();
            throw ex;
        }

生成 Hibernate:

Hibernate: select bb0_.idbb as col_0_0_ from Bb bb0_ where DESCR='B1' //SEARCH B1 ID
Hibernate: select bb0_.idbb as idbb1_0_, bb0_.descr as descr1_0_ from Bb bb0_ where bb0_.idbb=? //GET B1
Hibernate: select aas0_.BBIDBB as BBIDBB1_1_, aas0_.AAIDAA as AAIDAA1_, aa1_.idaa as idaa0_0_, aa1_.descr as descr0_0_ from AA_BB aas0_, Aa aa1_ where aas0_.AAIDAA=aa1_.idaa and aas0_.BBIDBB=? GET B1.Aas
Hibernate: select ccs0_.BBIDBB as BBIDBB1_1_, ccs0_.CCIDCC as CCIDCC1_, cc1_.idcc as idcc2_0_, cc1_.descr as descr2_0_ from BB_CC ccs0_, Cc cc1_ where ccs0_.CCIDCC=cc1_.idcc and ccs0_.BBIDBB=? GET B1.Ccs
Hibernate: insert into Aa (descr, idaa) values (?, ?) //OK
Hibernate: insert into Cc (descr, idcc) values (?, ?) //OK
Hibernate: insert into BB_CC (BBIDBB, CCIDCC) values (?, ?) //OK


... What about AA_BB record???? //!!!!!!!!

为什么joinTable AA_BB没有填满？

感谢大家的关注。问候，弗朗西斯科。

Answer 1

当您有双向关联时，一侧是所有者侧(不带 mappedBy 属性的一侧)，另一侧是反向侧(具有 mappedBy 属性的一侧)。

Hibernate 仅考虑所有者方来了解两个实体之间是否存在关联。因此，如果 A 是 A 和 B 之间关系的所有者方，则必须将 B 实例添加到 A 的集合中才能使关联持久化。将 A 实例添加到 B 的集合中没有任何效果。

一般来说，您负责维护对象图的一致性，因此您应该确保所有者端(至少)始终更新。