🚀

예제 도메인 모델

@Entity
@Getter
@Setter
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@ToString(of = {"id", "username", "age"})
public class Member {

	@Id
	@GeneratedValue
	@Column(name = "member_id")
	private Long id;
	
	private String username;
	
	private int age;

	@ManyToOne(fetch = FetchType.LAZY)
	@JoinColumn(name = "team_id")
	private Team team;

	public Member(String username) {
		this(username, 0);
	}

	public Member(String username, int age) {
		this(username, age, null);
	}

	public Member(String username, int age, Team team) {
		this.username = username;
		this.age = age;
		if (team != null) {
			changeTeam(team);
		}
	}

	public void changeTeam(Team team) {
		this.team = team;
		team.getMembers().add(this);
	}
	
}

@Entity
@Getter @Setter
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@ToString(of = {"id", "name"})
public class Team {

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

	private String name;

	@OneToMany(mappedBy = "team")
	private List<Member> members = new ArrayList<>();

	public Team(String name) {
		this.name = name;
	}
}

@SpringBootTest
@Transactional
@Commit
public class MemberTest {

	@PersistenceContext
	EntityManager em;

	@Test
	public void testEntity() {
		Team teamA = new Team("teamA");
		Team teamB = new Team("teamB");
		em.persist(teamA);
		em.persist(teamB);
		Member member1 = new Member("member1", 10, teamA);
		Member member2 = new Member("member2", 20, teamA);
		Member member3 = new Member("member3", 30, teamB);
		Member member4 = new Member("member4", 40, teamB);
		em.persist(member1);
		em.persist(member2);
		em.persist(member3);
		em.persist(member4);

		//초기화
		em.flush();
		em.clear();

		//확인
		List<Member> members = em.createQuery("select m from Member m",
				Member.class)
			.getResultList();
		for (Member member : members) {
			System.out.println("member=" + member);
			System.out.println("-> member.team=" + member.getTeam());
		}
	}
}