休眠 - 如何只保留父母，让孩子保持原样

问题描述

我有一个父级实体Appartment，其中包含一个房间列表作为孩子。
我有一个表格来编辑公寓，在这个表格中，我列出了所有孩子的房间，仅供参考。房间被添加和编辑在一个单独的窗体中。

所以，因为我列出房间的公寓形式，我设置了lazyloading为false：

  @OneToMany 
 @JoinColumn（name =appartmentId）
 @LazyCollection（LazyCollectionOption.FALSE）
 private List< ;客房>房间; 
  

但是，如果我编辑公寓并将其存储，所有公寓房间会突然消失。在数据库中，它们不会被删除，而是被解除引用（如appartmentId = null）。

那么如何配置hibernate来只保留我的Appartment对象。而不是触摸孩子？

这是我的保存动作：

  public String save（）throws Exception {
 boolean isNew =（appartment.getAppartmentId（）== null）; 
 
 appartment = appartmentManager.save（appartment）; 
 
 String key =（isNew）？ appartment.added：appartment.updated; 
 saveMessage（getText（key））; 
 
返回SUCCESS; 
 
  

解决方案

这非常简单。无需重新填充您的孩子，或创建单独的DTO。

如果您永远不会坚持孩子，只需将joinable = false，updatable = false添加到联合列注释中即可。像这样：

  @OneToMany 
 @JoinColumn（name =appartmentId，insertable = false，updatable = false） 
 @Fetch（value = FetchMode.JOIN）
 private List< Room>房间; 
  

Can someone please help me understand how to configure hibernate to do what i want.

I have a parent entity "Appartment" with a List of "Room"s as children.I have a form to edit "Appartment"s and within that form i have listed all of the children "Room"s just for informative purposes. Rooms are added and edited in a separate form.

So because i am listing the rooms in the appartment-form i have set lazyloading to false:

    @OneToMany
@JoinColumn (name = "appartmentId")
@LazyCollection (LazyCollectionOption.FALSE)
private List<Room> room;

But if I edit an appartment and store it, all the appartments rooms suddenly dissappear. In the database they are not deleted, but dereferenced (as in appartmentId = null).

So how can I configure hibernate to only persist my Appartment-object. And not touch the children at all?

This is my save-action:

public String save() throws Exception {
    boolean isNew = (appartment.getAppartmentId() == null);

    appartment = appartmentManager.save(appartment);

    String key = (isNew) ? "appartment.added" : "appartment.updated";
    saveMessage(getText(key));

    return SUCCESS;
}

解决方案

This is really simple. No need to repopulate your children, or create separate DTO's.

If you are never going to persist the children just add insertable=false, updatable=false to your joincolumn annotation. Like this:

@OneToMany
@JoinColumn (name = "appartmentId", insertable = false, updatable = false)
@Fetch(value = FetchMode.JOIN)
private List<Room> room;

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