Question

我在尝试创建组合密钥（EmbeddedId）时遇到了Ebean问题。

这是我所拥有的草稿：

@Entity public class EntityA extends Model{
    @Id
    private String ID;

    @OneToMany
    private List<EntityB> listEntitesB; 

    public EntityA(){
        ID = UUID.randomUUID();
    }
}

@Entity public class EntityB extends Model{

    @EmbeddedId
    private EntityB_PK ID;

    @ManyToOne
    @JoinColumn(name="entityA_fk", referencedColumnName="listEntitiesB")
    private EntityA entityA; 

    public EntityB(String entityB_ID){
         ID = new EntityB_PK(UUID.randomUUID(), entityB_ID);
    }
}

@Embeddable public class EntityB_PK{
    private String entityB_ID;
    private String entityA_FK_ID;

    public EntityB_PK(String entB_ID, String entA_FK_ID){
       entityB_ID = entB_ID;
       entityA_FK_ID = entA_FK_ID;
    } 
}

注意：我使用Ebean 4.1.4和Java 1.6。

所以，这段代码运行良好，但有一个特权，我试图解决 - 数据库中的结果表如下所示：

entityB_ID [primary]
entityA_FK_ID [primary]
entityA_fk

正如您所看到的那样，考虑到＆＃34; entityA_FK_ID＆＃34;列。

我想要什么？

我希望能告诉Ebean使用列＆＃34; entityA_FK_ID＆＃34;对于@ManyToOne协会而不是创建它自己的专栏。

Answer 1

要解决这个问题，我们必须：

将EntityB.entityA映射到与EntityB.ID.entityA_FK_ID相同的列
设置＆＃39;可插入＆＃39;和'可更新的＆＃39; EntityB.entityA @JoinColumn注释的属性
覆盖EntityB.entityA的设置者

以下是代码：

EntityA.java：

@Entity 
public class EntityA extends Model {
    @Id
    private String ID;

    @OneToMany(mappedBy="entityA")
    public List<EntityB> listEntitesB; 

    public static Finder<String,EntityA> find = new Finder<String,EntityA>(
        String.class, EntityA.class
    ); 

    public EntityA() {
        ID = UUID.randomUUID().toString();
    }

    public String getID() {
        return ID;
    }
}

EntityB.java：

@Entity 
public class EntityB extends Model {

    @EmbeddedId
    private EntityB_PK ID;

    @ManyToOne
    @JoinColumn(name = "entityA_fk_id", insertable = false, updatable = false)
    private EntityA entityA; 

    public EntityA getEntityA() {
        return entityA;
    }

    public void setEntityA(EntityA aEntityA) {
        entityA = aEntityA;
        ID.entityA_FK_ID = aEntityA.getID();
    }

    public EntityB(String entityB_ID){
         ID = new EntityB_PK(UUID.randomUUID().toString(), entityB_ID);
    }

    public String getID() {
        return ID.entityB_ID;
    }
}

EntityB_PK.java：

@Embeddable 
public class EntityB_PK implements Serializable {

    public String entityB_ID;

    @Column(name="entityA_fk_id")
    public String entityA_FK_ID;

    public EntityB_PK(String entB_ID, String entA_FK_ID){
       entityB_ID = entB_ID;
       entityA_FK_ID = entA_FK_ID;
    } 

    @Override
    public int hashCode() {
        return entityB_ID.length() + entityA_FK_ID.length();
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) 
            return true;
        EntityB_PK b = (EntityB_PK)obj;
        if(b==null)
            return false;
        if (b.entityB_ID.equals(entityB_ID) && b.entityA_FK_ID.equals(entityA_FK_ID)) {
            return true;
        }
        return false;
    }
}

Ebean EmbeddedId映射列为ManyToOne关系

1 个答案: