> For the complete documentation index, see [llms.txt](https://dodeon.gitbook.io/study/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dodeon.gitbook.io/study/kimyounghan-orm-jpa/11-object-oriented-query-intermidiate/using-entity.md).

# Entity 직접 사용

![](/files/-MaNZPwiNJ7BDKR0qGHQ)

* JPQL에서 id 대신 Entity를 넣으면 SQL에서 자동으로 해당 Entity의 기본키를 사용한다.

## 기본키

```java
public class JpaMain {

    public static void main(String[] args) {
        String jpql = "select m from Member m where m = :member";

        List resultList = em.createQuery(jpql)
                .setParameter("member", member).getResultList();
    }
}
```

* Entity를 파라미터로 넘기는 방식

```java
public class JpaMain {

    public static void main(String[] args) {
        String jpql = "select m from Member m where m.id = :memberId";

        List resultList = em.createQuery(jpql)
                .setParameter("memberId", memberId).getResultList();
    }
}
```

* 식별자를 직접 전달하는 방식

```sql
select m.*
from Member m
where m.id = ?
```

* 둘 다 같은 SQL을 실행한다.

## 외래키

```java
public class JpaMain {

    public static void main(String[] args) {
        Team team = em.find(Team.class, 1L);
        // 엔티티를 파라미터로 바로 전달
        // 연관 관계 매핑 설정에서 적어둔 FK를 사용한다.
        String qlString = "select m from Member m where m.team = :team";

        List resultList = em.createQuery(qlString)
                .setParameter("team", team).getResultList();
    }
}
```

```java
public class JpaMain {

    public static void main(String[] args) {
        // 키를 파라미터로 전달
        String qlString = "select m from Member m where m.team.id = :teamId";

        List resultList = em.createQuery(qlString)
                .setParameter("teamId", teamId).getResultList();
    }
}
```

```sql
select m.*
from Member m
where m.team_id = ?
```

* 외래 키 역시 Entity를 사용할 수 있다.


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