如何使用hibernate连接两个表的字段？

yxyvkwin 于 2021-07-09 发布在 Java

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我有两个表和相关的javaMap。

CREATE TABLE country (
    code VARCHAR(3) PRIMARY KEY NOT NULL,
    name VARCHAR(100) NOT NULL
);

CREATE TABLE user (
    id INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
    name VARCHAR(100) NOT NULL,
    country_code VARCHAR(3),
    FOREIGN KEY ( country_code ) REFERENCES country ( code )
);

这是我的java实体。国家pojo：

@Entity
@Table(name = "country")
public class Country {

    @Id
    @Column (name = "code")
    private String code;

    @Column (name = "name")
    private String name;

和用户pojo：

@Entity
@Table(name = "user")
public class User implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;

    @Column(name = "name")
    private String name;

    @Column(name = "country_code")
    private String countryCode;

问题是我怎样才能加入 Contry.code 至 User.countryCode 在hibernate中使用注解？当我用hibernate创建用户对象时，我需要自动绑定这两个字段（code和countrycode）。

Java Hibernate hibernate-annotations

来源：https://stackoverflow.com/questions/22334630/how-to-join-fields-of-two-tables-using-hibernate

1条答案

按热度按时间

nuypyhwy1#

你需要 @OneToMany Map自 Country 至 User 实体及对应 @ManyToOne Map自 User 至 Country :

@Entity
@Table(name = "country")
public class Country {

    @Id
    @Column (name = "code")
    private String code;

    @Column (name = "name")
    private String name;

    @OneToMany(mappedBy = "country")
    private Set<User> users;
}

@Entity
@Table(name = "user")
public class User implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;

    @Column(name = "name")
    private String name;

    @ManyToOne
    @JoinColumn(name = "country_code")
    private Country country;
}

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如何使用hibernate连接两个表的字段？

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