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Question

我在ORM类层次结构中的对象上遇到连接表的问题，其中连接列不是基类的主键，因为它是一个滞后数据库结构。以下是表格设计的示例：

CREATE TABLE "SCH"."FOO"
(
        "OWNERID"       NUMBER(10,0) NOT NULL ENABLE,
        "FOOID"         NUMBER(10,0) NOT NULL ENABLE,
        CONSTRAINT "FOO_PK" PRIMARY KEY ("OWNERID", "FOOID")
        CONSTRAINT "FOO_FK1" FOREIGN KEY ("OWNERID") REFERENCES "SCH"."OWNERS" ("OWNERID") ENABLE
)

CREATE TABLE "SCH"."BAR"
(
        "BARID"             NUMBER(10,0) NOT NULL ENABLE,
        "FOOID"             NUMBER(10,0)
        CONSTRAINT "BAR_PK" PRIMARY KEY ("BARID")
)

以下是映射（删除了不必要的信息）

@Entity
@IdClass(FooId.class)
@Table(name = "FOO")
public class Foo implements java.io.Serializable
{
    @Id
    @Column(name = "OWNERID")
    private BigInteger ownerId;

    @Id
    @SequenceGenerator(name = "FOO_GENERATOR", sequenceName = "SEQ_FOO")
    @GeneratedValue(generator = "FOO_GENERATOR")
    @Column(name = "FOOID")
    private BigInteger id;

    @OneToMany(fetch = FetchType.LAZY)
    @JoinColumn(name = "FOOID", referencedColumnName = "FOOID")
    @Fetch(value = FetchMode.SUBSELECT)
    @Cascade(value = {CascadeType.ALL})
    private Set<Bar> bar = new LinkedHashSet<Bar>(0);
}


@Entity
@Table(name = "BAR")
public class Bar implements java.io.Serializable
{
    @Id
    @Column(name = "BARID")
    private BigInteger id;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "FOOID", referencedColumnName = "FOOID")
    private Foo foo;
}

失败，但有例外：

Caused by: org.hibernate.AnnotationException: referencedColumnNames(FOOID) of com.package.Bar.foo referencing com.package.Foo not mapped to a single property
    at org.hibernate.cfg.BinderHelper.createSyntheticPropertyReference(BinderHelper.java:204)
    at org.hibernate.cfg.ToOneFkSecondPass.doSecondPass(ToOneFkSecondPass.java:114)
    at org.hibernate.cfg.Configuration.processEndOfQueue(Configuration.java:1580)
    at org.hibernate.cfg.Configuration.processFkSecondPassInOrder(Configuration.java:1503)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1419)
    at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1375)

你能帮忙解决一下吗？

Answer 1

您不得两次映射双向关联。必须使用mappedBy属性

将One侧标记为Many侧的反面

@OneToMany(fetch = FetchType.LAZY, mappedBy = "foo")
@Fetch(value = FetchMode.SUBSELECT)
@Cascade(value = {CascadeType.ALL})
private Set<Bar> bar = new LinkedHashSet<Bar>(0);

...

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "FOOID", referencedColumnName = "FOOID")
private Foo foo;

没有理由告诉Hibernate两次关联是由连接列FOOID映射的。这样做实际上是一个错误，因为它定义了两个不同的单向关联，而不是一个双向关联。

修改

以上应该可行，但不是由于以下Hibernate错误：这是一个Hibernate错误。请参阅HHH-4284。

要解决此问题，由于FOOID足以确保唯一性，因此解决方案是从所有者ID和@Id注释中删除@IdClass注释。

Answer 2

你可以这样做......它应该有效 -

@Entity
@IdClass(FooId.class)
@Table(name = "FOO")
public class Foo implements java.io.Serializable
{
    @Id
    @Column(name = "OWNERID")
    private BigInteger ownerId;

    @Id
    @SequenceGenerator(name = "FOO_GENERATOR", sequenceName = "SEQ_FOO")
    @GeneratedValue(generator = "FOO_GENERATOR")
    @Column(name = "FOOID")
    private BigInteger id;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JoinColumn(name = "FOOID",nullable=false)
    @ForeignKey(name = "fk")     
    private Set<Bar> bar = new LinkedHashSet<Bar>(0);
}


@Entity
@Table(name = "BAR")
public class Bar implements java.io.Serializable
{
    @Id
    @Column(name = "BARID")
    private BigInteger id;

    @ManyToOne(fetch=FetchType.LAZY)
    @JoinColumn(name = "FOOID", updatable = false, insertable = false, nullable=false)  
     private Foo foo;
}

Answer 3

您在FOO表中使用了复合主键。所以你应该尝试@EmbeddedId属性，你应该在BAR实体中需要两个列“OWNER_ID”和“FOO_ID”，它们与FOO实体连接。

如何在非主键列上连接表？

3 个答案:

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