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hibernate - 合并两个实体并获取数据

问题描述

我有两个实体类 FlcDrawingRequests 和 FlcDrawingRequestStats 。从两个表中获取数据我尝试使用以下查询从两个表中获取数据。无法获取数据。请任何人帮助我。

 private static final String querystat = "select dr, ds from 
 FlcDrawingRequests AS dr,FlcDrawingRequestStats AS ds where dr.id=ds.request_id";

下面是两个实体类

FlcDrawingRequests

@Entity(name = "FlcDrawingRequests")
@Table(name = "drawing_requests", catalog = FlcWsDao.DB_SCHEMA_NAME)
public class FlcDrawingRequests {

    @Id
    private String id;
    @Column(name = "creation_time", nullable = false, updatable = false)
    private Date creation_time;
    @Column(name = "drawing_spec_format", length = 16)
    private String drawing_spec_format;
    @Column(name = "end_time")
    private Date end_time;
}

FlcDrawingRequests

@Entity(name = "FlcDrawingRequestStats")
@Table(name = "drawing_request_stats", catalog = FlcWsDao.DB_SCHEMA_NAME)
public class FlcDrawingRequestStats {
    @Id
    private String request_id;
    @Column(name = "bb", length = 11)
    private Integer bb;
    @Column(name = "car_offset_g", length = 11)
    private Integer car_offset_g;
    @Column(name = "car_sling_type", length = 32)
    private String car_sling_type;
    @Column(name = "car_type", length = 16)
    private String car_type;
    @Column(name = "ch", length = 11)
    private Integer ch;
}

下面是查询执行：

StringBuilder queryBuilder = new StringBuilder(querystat);
System.out.println("startDate--->" + startDate);
Query query =getEntityManager().createQuery(queryBuilder.toString());
System.out.println("query.list();--->" + query.getResultList().size());
return query.getResultList();

标签： hibernatejpa

解决方案

 private static final String querystat = "SELECT dr, ds FROM 
 FlcDrawingRequests dr,FlcDrawingRequestStats ds WHERE dr.id LIKE ds.request_id";

并且结果必须存储在其中，List<Object[2]>因此您必须具有：

List<Object[2]> result=query.getResultList();

所以这里有一个大小等于两个的表列表，列表中的每个元素都包含两个对象，第一个是 FlcDrawingRequests，第二个是 FlcDrawingRequestStats。

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