[JPA_Basic] Bulk 연산

이 글은 김영한의 [자바 ORM 표준 JPA 프로그래밍 - 기본편]을 수강하며 정리한 글입니다.

 

👉 기본 환경

- Language: Java

- DB: H2 Database

- IDE: IntelliJ

 

 

Bulk 연산

⌨️ 코드

public class Main {
    public static void main(String[] args) {
 
        // 생략
 
        try {
 
            Team teamA = new Team();
            teamA.setName("TeamA");
            em.persist(teamA);
 
            Team teamB = new Team();
            teamB.setName("TeamB");
            em.persist(teamB);
 
 
            Member memberA = new Member();
            memberA.setName("MemberA");
            memberA.setTeam(teamA);
            em.persist(memberA);
 
            Member memberB = new Member();
            memberB.setName("memberB");
            memberB.setTeam(teamA);
            em.persist(memberB);
 
            Member memberC = new Member();
            memberC.setName("memberC");
            memberC.setTeam(teamB);
            em.persist(memberC);
 
            String query = "update Member m set m.age = 20";
            int resultCnt = em.createQuery(query)
                    .executeUpdate();
 
            System.out.println("ResultCnt: " + resultCnt);
 
            Member findMember = em.find(Member.class, memberA.getId());
 
            System.out.println("memberA.getAge(): " + findMember.getAge());
 
            tx.commit(); // transaction 종료 후 commit
        } catch (Exception e) {
            tx.rollback(); // 문제가 생길 경우, rollback 진행
            e.printStackTrace();
        } finally {
            em.close(); // tx에 문제가 생기더라도 em 반드시 종료
        }
 
 
        emf.close();
        // 트랜잭션 단위로 관리되는 Entity Manager는 Tx가 종료되면 close가 되어야하지만, emf는 Application 종료 시, close되어야 함
 
    }
}

- executeUpdate()

    - 벌크 연산은 영속성 컨텍스트를 무시하고 데이터베이스에 직접 쿼리 전송

        - DB: memberA.getAge()는 20

        - 영속성 Context: memberA.getAge()는 20이 아닌 0으로 조회

 

🖨️발생한 쿼리

Hibernate: 
    /* update
        Member m 
    set
        m.age = 20 */ update
            Member 
        set
            age=20
ResultCnt: 3
memberA.getAge(): 0
 

 

 

⭐ 벌크 연산 후, 영속성 컨텍스트 초기화

⌨️ 코드

public class Main {
    public static void main(String[] args) {
 
        // 생략
 
        try {
 
            Team teamA = new Team();
            teamA.setName("TeamA");
            em.persist(teamA);
 
            Team teamB = new Team();
            teamB.setName("TeamB");
            em.persist(teamB);
 
 
            Member memberA = new Member();
            memberA.setName("MemberA");
            memberA.setTeam(teamA);
            em.persist(memberA);
 
            Member memberB = new Member();
            memberB.setName("memberB");
            memberB.setTeam(teamA);
            em.persist(memberB);
 
            Member memberC = new Member();
            memberC.setName("memberC");
            memberC.setTeam(teamB);
            em.persist(memberC);
 
            String query = "update Member m set m.age = 20";
            int resultCnt = em.createQuery(query)
                    .executeUpdate();
 
            System.out.println("ResultCnt: " + resultCnt);
 
            em.clear();
 
            Member findMember = em.find(Member.class, memberA.getId());
 
            System.out.println("memberA.getAge(): " + findMember.getAge());
 
            tx.commit(); // transaction 종료 후 commit
        } catch (Exception e) {
            tx.rollback(); // 문제가 생길 경우, rollback 진행
            e.printStackTrace();
        } finally {
            em.close(); // tx에 문제가 생기더라도 em 반드시 종료
        }
 
 
        emf.close();
        // 트랜잭션 단위로 관리되는 Entity Manager는 Tx가 종료되면 close가 되어야하지만, emf는 Application 종료 시, close되어야 함
 
    }
}

 

🖨️발생한 쿼리

Hibernate: 
    /* update
        Member m 
    set
        m.age = 20 */ update
            Member 
        set
            age=20
ResultCnt: 3
Hibernate: 
    select
        member0_.id as id1_0_0_,
        member0_.age as age2_0_0_,
        member0_.name as name3_0_0_,
        member0_.TEAM_ID as team_id5_0_0_,
        member0_.type as type4_0_0_ 
    from
        Member member0_ 
    where
        member0_.id=?
memberA.getAge(): 20
 

새로운 select query 발생