JPA ManyToMany坚持 [英] JPA ManyToMany persist

问题描述

我有一个 NOTIFICATION 表，它包含一个ManyToMany关联：

  @Entity 
 @Table（name =NOTIFICATION）
 @NamedQuery（name =Notification.findAll，query =SELECT f FROM Notification f）
 public class Notification {
 
 **某些列定义对于我的个案不重要
 COD，DATE，ID_THEME，ID_TYP，IC_ARCH，ID_CLIENT，INFOS，NAME，TITRE_NOT，ID_NOT 
 ** / 
 
 @ManyToMany 
 @JoinTable（
 name =PJ_PAR_NOTIF
，joinColumns = {
 @JoinColumn（name =ID_NOTIF）
} 
，inverseJoinColumns = {
 @JoinColumn（name =ID_PJ_GEN）
} 
）
私人列表< PiecesJointesGen> piecesJointesGens; 
 
 
 
 $ b $ p 
 $ b 
所以，我有一个关联表，名为 PJ_PAR_NOTIF 。
 
 
 
我尝试坚持一个通知实体。这里是来自Value Object的piecesJointesGens初始化： 
 
 
  @PersistenceContext（unitName =pu / middle）
 
 private EntityManager entityMgr; 
 
 FoaNotification lFoaNotification = new FoaNotification（）; 
 
（PieceJointeGenVO lPJGenVO：pNotificationVO.getPiecesJointes（））{
 PiecesJointesGen lPiecesJointesGen = new PiecesJointesGen（）; 
 lPiecesJointesGen.setLienPjGen（lPJGenVO.getLienPieceJointeGen（））; 
 lPiecesJointesGen.setIdPjGen（lPJGenVO.getIdPieceJointeGen（））; 
 lNotification.getFoaPiecesJointesGens（）。add（lFoaPiecesJointesGen）; 
} 
 
 entityMgr.persist（pNotification）; 
  
坚持不起作用。 JPA为我的通知对象生成第一个插入，这是正常的：
 插入
到
 NOTIFICATION 
（COD，DATE，ID_THEME，ID_TYP，IC_ARCH，ID_CLIENT，INFOS，NAME，TITRE_NOT，ID_NOT）
值
（？，？，？，？，？，？，？，？然后，JPA尝试在我的关联表中插入值，但片断jointesGen不会暂时存在：
 插入
到
中PJ_PAR_NOTIF 
（ID_NOTIF，ID_PJ_GEN）
值
（？，？）
  
所以，我有这个错误：
  GRAVE：EJB异常:: java.lang.IllegalStateException：org.hibernate.TransientObjectException：对象引用未保存的瞬态实例 - 保存在冲洗前的瞬间实例：com.entities.PiecesJointesGen 
  
有没有办法告诉JPA插入 piecesJointesGen 在 PJ_PAR_NOTIF 之前ert？
解决方案 
修改 piecesJointesGens 映射到 @ManyToMany（cascade = CascadeType.PERSIST）。  
I have a NOTIFICATION table who contains one ManyToMany association :
@Entity
@Table(name="NOTIFICATION")
@NamedQuery(name="Notification.findAll", query="SELECT f FROM Notification f")
public class Notification {

/** SOME COLUMN DEFINITION NOT IMPORTANT FOR MY CASE
    COD, DATE, ID_THEME, ID_TYP, IC_ARCH, ID_CLIENT, INFOS, NAME, TITRE_NOT, ID_NOT
**/

        @ManyToMany
        @JoinTable(
            name="PJ_PAR_NOTIF"
            , joinColumns={
                @JoinColumn(name="ID_NOTIF")
                }
            , inverseJoinColumns={
                @JoinColumn(name="ID_PJ_GEN")
                }
            )
        private List<PiecesJointesGen> piecesJointesGens;
}
So, I have an association table called PJ_PAR_NOTIF.

I try to persist a Notification entity. Here is piecesJointesGens initialisation, from a Value Object :
@PersistenceContext(unitName="pu/middle")

private EntityManager entityMgr;

FoaNotification lFoaNotification = new FoaNotification();

for(PieceJointeGenVO lPJGenVO : pNotificationVO.getPiecesJointes()){
        PiecesJointesGen lPiecesJointesGen = new PiecesJointesGen();
        lPiecesJointesGen.setLienPjGen(lPJGenVO.getLienPieceJointeGen());
        lPiecesJointesGen.setIdPjGen(lPJGenVO.getIdPieceJointeGen());
        lNotification.getFoaPiecesJointesGens().add(lFoaPiecesJointesGen);
}

entityMgr.persist(pNotification);
The persist doesn't work. JPA generate a first insert for my Notification object, that is ok :
insert 
into
    NOTIFICATION
    (COD, DATE, ID_THEME, ID_TYP, IC_ARCH, ID_CLIENT, INFOS, NAME, TITRE_NOT, ID_NOT) 
values
    (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
Then, JPA try to insert values in my association table, but piecesJointesGen doesn't exists for the moment :
insert 
into
    PJ_PAR_NOTIF
    (ID_NOTIF, ID_PJ_GEN) 
values
    (?, ?)
So, I have this error :
GRAVE: EJB Exception: : java.lang.IllegalStateException: org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.entities.PiecesJointesGen
Is there a way to tell JPA to insert piecesJointesGen before the PJ_PAR_NOTIF insert ?
解决方案
Modify piecesJointesGens mapping to @ManyToMany(cascade = CascadeType.PERSIST). 

                        
这篇关于JPA ManyToMany坚持的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！