如何在 JPA 中选择和订购 EmbeddedID

Question

I have one table with a composite primary key:

public class IdmTenantBoard implements Serializable {
private static final long serialVersionUID = 1L;

@EmbeddedId
private IdmTenantBoardPK id;

@Column(name="board_display_name")
private String boardDisplayName;

@Column(name="board_name")
private String boardName;

The embedded class looks like this:

public class IdmTenantBoardPK implements Serializable {
//default serial version id, required for serializable classes.
private static final long serialVersionUID = 1L;

@Column(name="board_id")
private int boardId;

@Column(name="tenant_id")
private String tenantId;

The method I am using to call query is as follows:

public String getMaxBoardId(){
      TypedQuery<String> query = entityManager.createQuery("select o from IdmTenantBoard o order by o.IdmTenantBoardPK.boardId desc",String.class);
      query.setMaxResults(1);
      List<String> lResults = query.getResultList();
      String maxBoardId=null;
      if((null!=lResults)&&(!lResults.isEmpty())){
          maxBoardId=lResults.get(0);
      }
      return maxBoardId;
}

What do I need to get the boardId sorted in Descending order? I am getting the following error:

Caused by: org.hibernate.QueryException: could not resolve property: IdmTenantBoardPK of: com.newrubric.idm.common.entities.IdmTenantBoard [select o from com.newrubric.idm.common.entities.IdmTenantBoard o order by o.IdmTenantBoardPK.boardId desc]

Answer 1

In following IdmTenantBoardPK is type of the embedded id and name of the property is id :

@EmbeddedId
private IdmTenantBoardPK id;

That's why o.IdmTenantBoardPK.boardId cannot be used in queries. Instead of it o.id.boardId should be used.

Answer 2

这里 'id' 是属性名称，因此使用o.id.boardId而不是o.IdmTenantBoardPK.boardId 。

Answer 3

Using '.' operator we can specify sorting functionality on embeddedId fields.

@Embeddable
public class ProjectId implements Serializable {

    private static final long serialVersionUID = 1L;

    @Column(name = "PROJECT_NAME")
    private String projectName;

    @Column(name = "ORGANIZATION")
    private String organization;

    ......
    ......
}

@Entity
@Table(name = "projects")
public class Project {

    @EmbeddedId
    private ProjectId projectId;

    @Column(name = "STARTED_TIME")
    private Timestamp startedTime;

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

    @Column(name = "DESCRIPTION")
    private String description;

    ......
    ......
}

As you see above snippet ProjectId is a composite key for the entity Project. I can specify sorting on organization field like below.

Sort sort = new Sort(Direction.ASC, Arrays.asList("projectId.organization"));

Demo Application link .

Answer 4

I had the same issue. Try this, it works like a charm.

Add this to your actual code

Sort sort = Sort.by(Sort.Direction.DESC,"projectId.organization");

Add this method to the Repository

List<AccessoriesFile> findByorganization(String organization, Sort sort);