使用Hibernate進行內部聯接？

Question

我有一個用戶：

@Entity
@Table(name = UserEntity.TABLE_NAME)
public class UserEntity {
  ...
  private List<TeamEntity> teams = new ArrayList<TeamEntity>();
  ...
  @ManyToMany(mappedBy="users" , fetch = FetchType.LAZY)
  public List<TeamEntity> getTeams() {
    return teams;
  }
}

和一個團隊：

@Entity
@Table(name = TeamEntity.TABLE_NAME)
public class TeamEntity {
   ...
   private List<UserEntity> users = new ArrayList<UserEntity>();
   ...
   @ManyToMany (fetch = FetchType.LAZY)
  @JoinTable(name= TeamEntity.TEAM_USER_TABLE,joinColumns=@JoinColumn(name=TeamEntity.TEAM_ID, referencedColumnName="ID",
      insertable = true, updatable = false, nullable = false),
      inverseJoinColumns=@JoinColumn(name=TeamEntity.USER_ID, referencedColumnName="ID",
      insertable = true, updatable = false, nullable = false),
      uniqueConstraints = @UniqueConstraint(columnNames = {TeamEntity.TEAM_ID, TeamEntity.USER_ID}))
  public List<UserEntity> getUsers() {
    return users;
  }
}

如果我有該用戶的ID，該HQL查詢將檢索該用戶所屬的所有團隊嗎？

謝謝！

Answer 1

如果您不在內部聯接上執行任何操作，那么我就不會使用HQL ...

因為使用的是延遲加載，所以必須初始化teams集合...如果使用的是Eager訪存，則不需要第二行。

UserEntity user = (UserEntity) session.byId(UserEntity.class).load(id);
Hibernate.initialize(user.getTeams());

Answer 2

一種查詢方法是遵循JQPL（HQL或多或少是JPQL的超集）：

SELECT t 
FROM UserEntity u 
JOIN u.teams t 
WHERE u.id = :userId