eclipselink 2 OneToMany与一个关联表如何从一侧删除 [英] eclipselink 2 OneToMany with one association table how to delete from one side

问题描述

我具有以下实体关系: SideA:

i have the following entity relationship: SideA:

@Entity
@Table(name = "SideA")
    public class SideA {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long  id;

    @CascadeOnDelete
    @OneToMany(fetch = FetchType.LAZY, mappedBy = "sideA", cascade=CascadeType.ALL)
    private List<ABAssociation> association = new ArrayList<ABAssociation>();
}

B面:

@Entity
@Table(name = "SideB")
public class SideB {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long  id;

    @CascadeOnDelete
    @OneToMany(fetch = FetchType.LAZY, mappedBy = "sideB", cascade=CascadeType.ALL)
    private List<ABAssociation> association = new ArrayList<ABAssociation>();
}

ABA关联:

@Entity
@Table(name = "ABAssociation")
public class ABAssociation {

   @EmbeddedId
   private ABAssociationPK pk = new ABAssociationPK();
   @ManyToOne(cascade=CascadeType.MERGE)
   @MapsId("aId")
   private SideA sideA;

   @ManyToOne(cascade=CascadeType.MERGE)
   @MapsId("bId")
   private SideB sideB;
}

ABAssociationPK:

ABAssociationPK:

@Embeddable
public class ABAssociationPK implements java.io.Serializable{
    private long aId;
    private long bId;
}

我的问题是，当我删除一侧时，数据库会删除ABAssociation中的行，但仍保留在缓存中.

my problem is when i delete one side, the database delete the row in ABAssociation , but still stay in cache.

测试代码如下:

SideA a = new SideA();
SideB b = new SideB();
entitymanager.persist(a);
entitymanager.persist(b);

ABAssociation ab = new ABAssociation()
ab.setSideA(a);
ab.setSideB(b);
entitymanager.persist(ab);

a.getABAssociationList().add(ab);
b.getABAssociationList().add(ab);

a = entitymanager.merge(a);
b = entitymanager.merge(b);

entitymanager.delete(a);

由于删除了"a"，因此也应删除"a"和"b"之间的关系. 但是当我检查"b.getABAssociationList().size()"时，它仍然存在，即使数据库中的ABAssociation表中也没有行.

Since "a" was deleted, the relationship between "a" and "b" should be deleted too. but when i check the "b.getABAssociationList().size()" it still there, even there is no rows in ABAssociation table in DB.

这与共享缓存问题有关吗?

it this related to the share cache issue ?

推荐答案

在JPA中，您必须维护对象的关系.

In JPA you must maintain you object's relationships.

如果删除对象，则必须首先删除对该对象的所有引用.

If you remove an object, you must first remove all references to it.

看， http://en.wikibooks.org/wiki/Java_Persistence_then_after_update_up_ion_up_ion_relation_up_ion_side_up_Centre_side_side2.

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