Question

我目前正在使用Spring Data JPA和Hibernate开发Spring启动应用程序。我目前的设置如下：

我的TeamMapping存储库：

public interface TeamMembershipMapping Repository extends JpaRepository<TeamMembershipMapping, Integer>
{
    public List<TeamMembershipMapping> getByMemberId(Integer memberId, Pageable pageable);
}

My TeamMembershipMapping Entity：

@Entity
@Table(name = "teamMembership")
public class TeamMembershipMapping
{
    @Id
    private Integer teamMembershipId;

    @Column(table = "teamMembership", name = "memberId")
    private Integer memberId;

    @Enumerated
    @Column
    private TeamMembershipStatus status;

    @OneToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "teamId")
    private Team team;

    ---Getters and Setters---
}

我的团队实体：

@Entity
@Table(name = "team")
@SecondaryTable(name = "summaryTeam")
public class Team
{
    @Id
    private Integer teamId;

    @Column
    private String name;

    @Column
    private String description;

    @Column(table = "summaryTeam")
    private Integer wins;

    @Column(table = "summaryTeam", nullable = true)
    private Integer losses;

    --Getters and Setters---
}

现在我的问题是，当我调用getByMemberId来检索特定成员拥有的所有TeamMembershipMappings时，Hibernate会生成一个sql选择以获取所有TeamMappings，然后为每个Mappings执行sql选择以获取Team信息。因此，如果该成员是4个团队的一部分，那么1 + 4 sql选择何时可以在一个团队中完成。

那么如何强制Hibernate在一个大连接选择中获取所有信息？

Answer 1

在实体TeamMembershipMapping中，您可以创建一个这样的命名查询：

select tmm.team from TeamMembershipMapping tmm where tmm.memberId = :memberId;

这只是一个简单的查询。

如何强制Hibernate JPA创建连接查询

1 个答案: