복합키를 PK로 사용하기

특정 매핑 테이블을 구현하면서 복합키로 PK를 생성했던 케이스를 정리한 글입니다.

package com.arton.backend.follow.adapter.out.persistence.entity;

import com.arton.backend.infra.shared.BaseEntity;
import lombok.AccessLevel;
import lombok.Builder;
import lombok.Getter;
import lombok.NoArgsConstructor;

import javax.persistence.*;
import java.io.Serializable;
import java.time.LocalDateTime;

@Entity
@Table(name = "Follow", uniqueConstraints = @UniqueConstraint(columnNames = {"from_user", "to_user"}))
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@Getter
@IdClass(FollowEntity.PK.class)
public class FollowEntity extends BaseEntity {

    @Id
    @Column(name = "from_user", insertable = false, updatable = false)
    private Long fromUser;

    @Id
    @Column(name = "to_user", insertable = false, updatable = false)
    private Long toUser;

    @Builder
    public FollowEntity(LocalDateTime createdDate, LocalDateTime updatedDate, Long fromUser, Long toUser) {
        super(createdDate, updatedDate);
        this.fromUser = fromUser;
        this.toUser = toUser;
    }

    public static class PK implements Serializable {
        Long fromUser;
        Long toUser;
    }

}

static 대신 직접 클래스를 따로 만들어서 사용했던 케이스 입니다.

package com.arton.backend.zzim.domain;

import lombok.*;

import java.io.Serializable;

@NoArgsConstructor(access = AccessLevel.PROTECTED)
@AllArgsConstructor
@Getter
@EqualsAndHashCode
public class PerformanceZzimCompoundKey implements Serializable {
    private Long performance;
    private Long user;
}

package com.arton.backend.zzim.adapter.out.persistence.entity;

import com.arton.backend.infra.shared.BaseEntity;
import com.arton.backend.performance.adapter.out.persistence.entity.PerformanceEntity;
import com.arton.backend.user.adapter.out.persistence.entity.UserEntity;
import com.arton.backend.zzim.domain.PerformanceZzimCompoundKey;
import lombok.*;

import javax.persistence.*;
import java.time.LocalDateTime;

@Getter
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@AllArgsConstructor
@Entity
@Table(name = "Performance_Zzim")
@ToString
@IdClass(PerformanceZzimCompoundKey.class)
public class PerformanceZzimEntity extends BaseEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Id
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "user_id")
    private UserEntity user;

    @Id
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "performance_id")
    private PerformanceEntity performance;

    public void setUser(UserEntity user) {
        this.user = user;
        if (!user.getPerformanceZzims().contains(this)) {
            user.getPerformanceZzims().add(this);
        }
    }
    @Builder
    public PerformanceZzimEntity(LocalDateTime createdDate, LocalDateTime updateDate, Long id, UserEntity user, PerformanceEntity performance) {
        super(createdDate, updateDate);
        this.id = id;
        this.user = user;
        this.performance = performance;
    }
}