无交叉联接的JPA联接

我试图在以下表格之间建立一种关系

结合

@Entity
@NamedQuery(name="Combine.findAll", query="SELECT c FROM Combine c")
@Table(name="COMBINE")
public class Combine implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    private int id;

    private int artistid;

    private int automated;

    private int eventid;

    private int locationid;

    @Column(name="main_artist")
    private int mainArtist;

    public Combine() {
    }

事件

它当前所做的是使用以下TypedQuery生成与表的交叉联接

               StringBuffer sb = new StringBuffer();
sb.append("SELECT e FROM Event e, Combine c, Location l ");
sb.append("where e.id = c.eventid and l.id = c.locationid ");
sb.append("and e.time>=NOW() and e.soldOut='0' and e.active>=1");

这就产生了

select event0_.id as id1_26_,
 event0_.active as active2_26_,
  event0_.addbyspider as addbyspi3_26_,
   event0_.automated as automate4_26_,
    event0_.description as descript5_26_,
     event0_.doorsopen as doorsope6_26_,
      event0_.endtime as endtime7_26_,
       event0_.lastfm as lastfm8_26_,
        event0_.latest_update as latest_u9_26_,
         event0_.minimumageid as minimum10_26_,
          event0_.name as name11_26_,
           event0_.nolatertime as nolater12_26_,
            event0_.podiuminfo as podiumi13_26_,
             event0_.short_description as short_d14_26_,
              event0_.sold_out as sold_ou15_26_,
               event0_.time as time16_26_,
                event0_.update_by_bot as update_17_26_
                 from
                  event event0_
                   cross join COMBINE combine1_
                    cross join location location2_
                    where event0_.id=combine1_.eventid and location2_.id=combine1_.locationid and event0_.time>=now() and event0_.sold_out='0' and event0_.active>=1 limit ?

我根本不想创建

交叉联接

，而是希望在表之间创建

内部联接

。我怎样才能做到这一点

OneToOne有点问题，因为它无法构建到服务器。有人知道为什么这样不行吗

@OneToOne
@JoinColumn(name="eventid")
private List<Combine> combine;

@OneToOne
@JoinColumn（name=“eventid”）
私有列表合并；

您必须对实体中的关系进行建模。请参见

@ManyToOne

，

@onttomy

等等。我尝试了不同的关系，但没有成功，我如何在event.id=combine.eventid和combine.locationid=location.id之间创建关系？你大约一天前发布了完全相同的内容，我当时说，你在事件中没有关系可以合并，对于多个M-N关系的联接表，您也在使用table COMBINE。在考虑查询之前，您需要修复您的建模！现在你删除帖子并再次发布。答案是一样的问题是我没有实际创建这些模型，也没有实际使用JPA，所以我不确定“修复”什么。如果你能给我一个关于我的情况的例子，让我朝着正确的方向前进，我将非常感激。正如另一篇帖子所说（在你删除它之前），你可以使用JOIN来浏览关系。“从事件e中选择e加入e.combine c…”将获得加入到合并实体。任何JPQL教程都会告诉您如何进行连接

select event0_.id as id1_26_,
 event0_.active as active2_26_,
  event0_.addbyspider as addbyspi3_26_,
   event0_.automated as automate4_26_,
    event0_.description as descript5_26_,
     event0_.doorsopen as doorsope6_26_,
      event0_.endtime as endtime7_26_,
       event0_.lastfm as lastfm8_26_,
        event0_.latest_update as latest_u9_26_,
         event0_.minimumageid as minimum10_26_,
          event0_.name as name11_26_,
           event0_.nolatertime as nolater12_26_,
            event0_.podiuminfo as podiumi13_26_,
             event0_.short_description as short_d14_26_,
              event0_.sold_out as sold_ou15_26_,
               event0_.time as time16_26_,
                event0_.update_by_bot as update_17_26_
                 from
                  event event0_
                   cross join COMBINE combine1_
                    cross join location location2_
                    where event0_.id=combine1_.eventid and location2_.id=combine1_.locationid and event0_.time>=now() and event0_.sold_out='0' and event0_.active>=1 limit ?

@OneToOne
@JoinColumn(name="eventid")
private List<Combine> combine;