Hibernate JPA Annotations 1到0..1的关系(Hibernate JPA Annotations 1 to 0..1 relationship)

 我正在尝试设置1to0..1（零或一）关系，但遇到了问题。 
 
 现在我的假设是使用@OneToMany，而不是@OneToOne。 
 
 基本上我希望我的“子”表将外键保存到“父”（我非常松散地使用子和父）。 我永远不需要独立加载“儿童” 
 
 这是我想要实现的基本表结构 
 
ITEM {
  ID
  RELATED_ITEM_ID
}

INVOICE {
  ID
}
CATALOGUE {
  ID
}
 
 作为Java类重新命名如下 
 
class Item {
...
}

class Invoice {
  @OneToMany(fetch=FetchType.EAGER, orphanRemoval = true, cascade = { javax.persistence.CascadeType.ALL })
  @Fetch(FetchMode.JOIN)
  @JoinColumn(name="RELATED_ITEM_ID", nullable=false)
  Set<Item> items;
}

class Catalogue {
  @OneToMany(fetch=FetchType.EAGER, orphanRemoval = true, cascade = { javax.persistence.CascadeType.ALL })
  @Fetch(FetchMode.JOIN)
  @JoinColumn(name="RELATED_ITEM_ID", nullable=false)
  Set<Item> items;
}
 
 上面的代码，如果我只在Hibernate中注册Invoice或Catalog将创建我想要的表，并且工作完美。 但是，只要我注册了Invoice和Catalog，hibernate就会抛出错误 
 
org.hibernate.MappingException: Duplicate property mapping of _itemsBackref found in package.name.Item

I am trying to setup a 1to0..1 (zero or one) relationship, but am running into issues.
 
Now my assumption is to use the @OneToMany, and not @OneToOne.
 
Basically I want my "child" table to hold the foreign key to the "parent" (I use child and parent very loosely). I never need to load "children" standalone
 
This is the basic table structure I want to achieve
 
ITEM {
  ID
  RELATED_ITEM_ID
}

INVOICE {
  ID
}
CATALOGUE {
  ID
}
 
Reprsented as Java classes like the following
 
class Item {
...
}

class Invoice {
  @OneToMany(fetch=FetchType.EAGER, orphanRemoval = true, cascade = { javax.persistence.CascadeType.ALL })
  @Fetch(FetchMode.JOIN)
  @JoinColumn(name="RELATED_ITEM_ID", nullable=false)
  Set<Item> items;
}

class Catalogue {
  @OneToMany(fetch=FetchType.EAGER, orphanRemoval = true, cascade = { javax.persistence.CascadeType.ALL })
  @Fetch(FetchMode.JOIN)
  @JoinColumn(name="RELATED_ITEM_ID", nullable=false)
  Set<Item> items;
}
 
The above code, if I only have Invoice or Catalogue registered in hibernate will create the tables as I want, and work perfectly. However, as soon as I have both Invoice and Catalogue registered, hibernate throws me the error
 
org.hibernate.MappingException: Duplicate property mapping of _itemsBackref found in package.name.Item

原文：https://stackoverflow.com/questions/7913963