[컴] JPA 의 entity 로 foreign key 설정하는 법

외래키 / hibernate / join / spring boot / spring / java / orm / 연결 / 관계 설정 / relation entity

JPA 의 entity 로 foreign key 설정하는 법

user table 의 profile_id 가 profile table 의 id 를 참조하도록 하는 예시이다.

아래 code example 이 있다.

import jakarta.persistence.CascadeType;
import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.JoinColumn;
import jakarta.persistence.OneToOne;

@Entity
public class User {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "profile_id", referencedColumnName = "id", nullable=false)
    private Profile profile;

    ...
}

import jakarta.persistence.Entity;
import jakarta.persistence.Id;
import jakarta.persistence.OneToOne;

import java.time.LocalDateTime;

@Entity
public class Profile {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    
    @OneToOne(mappedBy = "profile")
    private User user;

create table user (id bigint not null auto_increment, profile_id bigint not null, primary key (id)) engine=InnoDB;
create table profile (id bigint not null, primary key (id)) engine=InnoDB;
alter table user add constraint FKl6pykqur53o90qdnhjko0r8ni foreign key (profile_id) references profile (id);

어느 값이 어느값을 가리키는지는 아래 그림을 참고하자.

연결

See Also

1. Spring Data JPA One To One Relationship Mapping Example
2. java - When Should I Use @JoinColumn or @JoinTable with JPA? - Stack Overflow