spring-boot - Spring Boot 数据 jpa 中的内连接

Question

我正在使用 spring boot data jpa 1.4，我对它很陌生。
我的表定义是 here .它相当简单，有 2 个表(组和用户)。

群 表包含 group_id(primary key), group_name, group_active(values=Y/N)。
理想情况下，组表可以只有一行将 group_active 设置为 'Y'，其余的应该有 'N'

用户 表包含 user_id(主键)、user_name、group_id(来自组的外键)。

以下是我的实体类

群:

@Entity
@Table(schema = "HR",  name = "GROUPS")
public class Group {

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "GROUP_ID")
    private Long id;

    @Column(name = "GROUP_NAME")
    private String name;

    @Column(name = "GROUP_ACTIVE")
    private String active;

用户:

@Entity
@Table(schema = "HR", name = "USERS")
public class User {

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "USER_ID")
    private Long id;

    @Column(name = "USER_NAME")
    private String name;

    @Column(name = "GROUP_ID")
    private Long groupId;

    @ManyToMany
    @JoinTable(
        schema = "HR",
        name = "GROUPS",
        joinColumns = {@JoinColumn(table = "GROUPS", name = "GROUP_ID", insertable = false, updatable = false)},
        inverseJoinColumns = {@JoinColumn(table = "USERS", name = "GROUP_ID", insertable = false, updatable = false)}
    )
    @WhereJoinTable(clause = "GROUP_ACTIVE='Y'")
    private List<Group> group;

存储库类:

public interface UserRepository extends CrudRepository<User, Long>{        
    List<User> findByName (String name);
}

查询 : 这是我要执行的查询，就是一个简单的内连接。

  SELECT U.*
  FROM HR.USER U, HR.GROUP G
  WHERE U.GROUP_ID=G.GROUP_ID
      AND G.GROUP_ACTIVE='Y'
      AND U.USER_NAME=?

编写@JoinTable 或@JoinColumn 的正确方法是什么，这样我总是能找回一个属于事件组的名称为 的用户？

Answer 1

我已经根据您的设置进行了一些测试，解决方案需要使用过滤器(假设只有一个 Group_Activity = 'Y'):

集团实体

@Entity
@Table(schema = "HR",  name = "GROUPS")
public class Group {

     @OneToMany(mappedBy = "group")
     @Filter(name = "activityFilter")
     private Set<User> users;

用户实体

@Entity
@Table(schema = "HR", name = "USERS")
@FilterDef(name="activityFilter"
       , defaultCondition="group_id = 
              (select g.id from groups g where g.GROUP_ACTIVE='Y')")
public class User {

@ManyToOne
@JoinColumn(name = "group_id")
private Group group;

查询时

session.enableFilter("activityFilter");
session.createQuery("select u from Group g inner join g.users u where u.user_name = :userName");

另外 如果有许多事件 = 'Y' 的组，请尝试以下操作:

@FilterDef(name="activityFilter"
       , defaultCondition="group_id in
              (select g.id from group g where g.GROUP_ACTIVE='Y')")