Question

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

组表包含group_id（主键），group_name，group_active（值= Y / N）。理想情况下，组表只能有一行，其中group_active为'Y'，其余行应为'N'</ p>
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

组：

@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：这是我想要执行的查询，这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，以便我总是找回属于具有名称的活动组的一个用户？

Answer 1

我根据您的设置做了一些测试，解决方案需要使用过滤器（假设只有一个Group的Group_Activity ='Y'）：

群组实体

@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;

进行查询时

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

另外如果有很多活动组='Y'，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')")

Answer 2

尝试一下

node -v

内部连接在spring引导数据jpa中

2 个答案: