JPA 在 Embeddable 和 EmbeddedId 之间映射@ManyToOne

问题描述

我在 Spring Boot JPA 应用程序中有以下设置:

I have the following setup in my Spring Boot JPA application:

可嵌入

@Embeddable
public class LogSearchHistoryAttrPK {
    @Column(name = "SEARCH_HISTORY_ID")
    private Integer searchHistoryId;

    @Column(name = "ATTR", length = 50)
    private String attr;

    @ManyToOne
    @JoinColumn(name = "ID")
    private LogSearchHistory logSearchHistory;
    ...
}

EmbeddedId

@Repository
@Transactional
@Entity
@Table(name = "LOG_SEARCH_HISTORY_ATTR")
public class LogSearchHistoryAttr implements Serializable {
    @EmbeddedId
    private LogSearchHistoryAttrPK primaryKey;

    @Column(name = "VALUE", length = 100)
    private String value;
    ...
}

一对多

@Repository
@Transactional
@Entity
@Table(name = "LOG_SEARCH_HISTORY")
public class LogSearchHistory implements Serializable {
    @Id
    @Column(name = "ID", unique = true, nullable = false)
    private Integer id;

    @OneToMany(mappedBy = "logSearchHistory", fetch = FetchType.EAGER)
    private List<LogSearchHistoryAttr> logSearchHistoryAttrs;
    ...
}

数据库 DDL

CREATE TABLE log_search_history (
    id serial NOT NULL,
    ...
    CONSTRAINT log_search_history_pk PRIMARY KEY (id)
 );

CREATE TABLE log_search_history_attr (
    search_history_id INTEGER NOT NULL,
    attr CHARACTER VARYING(50) NOT NULL,
    value CHARACTER VARYING(100),
    CONSTRAINT log_search_history_attr_pk PRIMARY KEY (search_history_id, attr),
    CONSTRAINT log_search_history_attr_fk1 FOREIGN KEY (search_history_id) REFERENCES
        log_search_history (id)
);

当我去启动应用程序时，出现以下错误:

When I go to start the application, I get the following error:

引起:org.hibernate.AnnotationException:mappedBy 引用了一个未知的目标实体属性:com.foobar.entity.LogSearchHistory.logSearchHistoryAttrs 中的 com.foobar.entity.LogSearchHistoryAttr.logSearchHistory

我不知道为什么我会收到这个错误 - 映射看起来是正确的(对我来说).我的这个映射有什么问题?谢谢！

I am not sure why I am getting this error - the mapping looks correct (to me). What is wrong with this mapping that I have? Thanks!

推荐答案

您将 mappedBy 属性移动到可嵌入的主键中，因此该字段不再命名为 logSearchHistory而是 primaryKey.logSearchHistory.更改您的映射条目:

You moved the mappedBy attribute into an embeddable primary key, so the field is no longer named logSearchHistory but rather primaryKey.logSearchHistory. Change your mapped by entry:

@OneToMany(mappedBy = "primaryKey.logSearchHistory", fetch = FetchType.EAGER)
private List<LogSearchHistoryAttr> logSearchHistoryAttrs;

参考:JPA/Hibernate OneToMany 映射，使用复合主键.

您还需要使主键类 LogSearchHistoryAttrPK 可序列化.

You also need to make the primary key class LogSearchHistoryAttrPK serializable.

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