:단방향 연관관계 질문있습니다.

강의 :단방향 연관관계

20분 55초에서 쿼리가 안나온다는게

create table Team (

TEAM_ID bigint not null,

TEAM_NAME varchar(255),

primary key (TEAM_ID)

)

이게 안나오느다는건가요?

근데 persist로 db에 저장되서 안나온다고 하셨는데 12분에도 persist가 있는데도 쿼리가 나오는데요. 혹시 find 앞에 persist는 예외인건가요?

try {

Team team =new Team();

team.setName("TeamA");

em.persist(team);//영속 상태가 되면 pk값이 세팅 되고 영속 상태가 됨.

Member member = new Member();

member.setUsername("member1");

// member.setTeamId(team.getId());//연관관계 매핑 배우기 전 팀의 외래키를 만들어서 멤버에 조인함.

em.persist(member);

tx.commit();

}catch (Exception e){

tx.rollback();

}finally {

em.close();//엔티티 매니저가 내부적으로 데이터베이스를 물고 동작을 함.

}

emf.close();

}

단방향 연관관계 22분에서

em.flush();

em.clear();

을 추가하면 영속성 컨테스트를 db로 보내버리고 동기화 상태에서 1차캐시가 빈상태로 조회가능하다는것은 알겠는데요.

그래서 다른점이 혹시 아래 select문인가요?

Hibernate:

select

member0_.MEMBER_ID as MEMBER_I1_0_0_,

member0_.TEAM_ID as TEAM_ID3_0_0_,

member0_.USERNAME as USERNAME2_0_0_,

team1_.TEAM_ID as TEAM_ID1_1_1_,

team1_.TEAM_NAME as TEAM_NAM2_1_1_

from

Member member0_

left outer join

Team team1_

on member0_.TEAM_ID=team1_.TEAM_ID

where

member0_.MEMBER_ID=?

select
member0_.MEMBER_ID as MEMBER_I1_0_0_,
member0_.TEAM_ID as TEAM_ID3_0_0_,
member0_.USERNAME as USERNAME2_0_0_,
team1_.TEAM_ID as TEAM_ID1_1_1_,
team1_.TEAM_NAME as TEAM_NAM2_1_1_
from Member member0_
left outer join Team team1_ on member0_.TEAM_ID=team1_.TEAM_ID
where member0_.MEMBER_ID=?