Hibernate - 一对一关系单表继承答案

【问题标题】：Hibernate - One to one relation single table inheritanceHibernate - 一对一关系单表继承
【发布时间】：2019-08-22 09:03:47
【问题描述】：

我有 3 个实体 BaseFoo、FooAbc、FooAbcDetail。 FooAbc 扩展基本实体 BaseFoo。我正在尝试在FooAbc 和FooAbcDetail 之间建立一对一的关系。

@Data
@EqualsAndHashCode(callSuper = true)
@Entity
@Table(name = "foo")
@Audited
@AuditOverride(forClass = Auditable.class)
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "type_id", discriminatorType = DiscriminatorType.INTEGER)
public abstract class BaseFoo extends Auditable implements Serializable {

    @Id
    @Column(name = "id")
    private Long id;

    //other fields
}

@Data
@EqualsAndHashCode(callSuper = true)
@Entity
@Audited
@AuditOverride(forClass = BaseFoo.class)
@DiscriminatorValue("2")
public class FooAbc extends BaseFoo implements Serializable {

    @EqualsAndHashCode.Exclude
    @ToString.Exclude
    @NotAudited
    @OneToOne(mappedBy = "fooAbc",
              fetch = FetchType.LAZY,
              cascade = CascadeType.ALL,
              orphanRemoval = true,
              optional = false)
    private FooAbcDetail fooAbcDetail;

    //other fields
}

@Data
@Entity
@Table(name = "foo_abc_detail")
public class FooAbcDetail implements Serializable {

    @Id
    @Column(name = "foo_id"/* foo_abc_id (I tried both) */)
    private Long id;

    @ToString.Exclude
    @EqualsAndHashCode.Exclude
    @MapsId //also tried @MapsId("id")
    @OneToOne(fetch = FetchType.LAZY)
    private FooAbc fooAbc; //also tried BaseFoo

    //other fields
}

当项目启动 Hibernate 时抛出：

org.hibernate.MappingException：无法找到具有逻辑的列名称：org.hibernate.mapping.Table(public.foo_abc_detail) 中的 id 及其相关的超表和辅助表

这里有什么问题？

环境

休眠 5.3.10.Final
Spring Boot 2.1.7.RELEASE

【问题讨论】：

展示您如何设置foo_abc_detail 表
@XtremeBaumer 抱歉，我无法理解。你说的设置是什么意思？是 DDL 吗？
正是我们需要的
@XtremeBaumer 对不起，我迟到了。这里是。 CREATE TABLE foo_abc_detail ( foo_id bigint NOT NULL CONSTRAINT pk_foo_abc_detail PRIMARY KEY CONSTRAINT "fk_AwfsRYAAxLwavrnv16Re" REFERENCES foo ON UPDATE CASCADE ON DELETE CASCADE DEFERRABLE --other columns );

标签： java hibernate one-to-one single-table-inheritance

【解决方案1】：

此错误告诉您foo_abc_detail 表上没有名为foo_id 的列。foo_abc_detail 上的列只是名为id。

@Data
@EqualsAndHashCode(callSuper = true)
@Entity
@Table(name = "foo")
@Audited
@AuditOverride(forClass = Auditable.class)
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "type_id", discriminatorType = DiscriminatorType.INTEGER)
public abstract class BaseFoo extends Auditable implements Serializable {

    @Id
    @Column(name = "id")
    private Long id;

    //other fields
}

@Data
@EqualsAndHashCode(callSuper = true)
@Entity
@Audited
@AuditOverride(forClass = BaseFoo.class)
@DiscriminatorValue("2")
public class FooAbc extends BaseFoo implements Serializable {

    @EqualsAndHashCode.Exclude
    @ToString.Exclude
    @NotAudited
    @OneToOne(mappedBy = "fooAbc",
              fetch = FetchType.LAZY,
              cascade = CascadeType.ALL,
              orphanRemoval = true,
              optional = false)
    private FooAbcDetail fooAbcDetail;

    //other fields
}

@Data
@Entity
@Table(name = "foo_abc_detail")
public class FooAbcDetail implements Serializable {

    @Id
    @Column(name = "id")
    private Long id;

    @ToString.Exclude
    @EqualsAndHashCode.Exclude
    @MapsId //also tried @MapsId("id")
    @OneToOne(fetch = FetchType.LAZY)
    private FooAbc fooAbc; //also tried BaseFoo

    //other fields
}

【讨论】：

请提供表foo_abc_detail的列结构

【解决方案2】：

好吧，我解决了。我不知道这是否是最好的方法，但它有效！我通过@JoinColumn 替换了@MapsId 注释。 FooAbcDetail 类的最终结果如下。

@Data
@Entity
@Table(name = "foo_abc_detail")
public class FooAbcDetail implements Serializable {

    @Id
    @Column(name = "id")
    private Long id;

    @ToString.Exclude
    @EqualsAndHashCode.Exclude
    @OneToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "id", referencedColumnName = "id", nullable = false)
    private FooAbc fooAbc;

}

【讨论】：