JPA 2個Inheritance.TABLE_PER_CLASS與抽象的關係

Question

我有以下實體：

@Entity 
public class Owner{ 
@Id 
@Column(name = "OWNER_ID") 

    @OneToMany() 
    @JoinColumn(name = "OWNER_ID") 
    private Set<Parent> parents; 
    ... 
} 

@Entity 
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS) 
public class Parent{ 
    @Id 
    @Column(name = "PARENT_ID") 
    ... 
} 

@Entity 
public class ChildA extends Parent{ 
    ... 
} 

@Entity 
public class ChildB extends Parent{ 
    ... 
} 

}

的問題是，我得到下面的異常，當我試圖堅持一個業主與父元素：

org.springframework.dao.InvalidDataAccessResourceUsageException：無法插入集合：[sample.Owner.parents＃1]; SQL [更新父集OWNER_ID =？ PARENT_ID =？]; org.springframework.dao.InvalidDataAccessResourceUsageException：無法插入集合：[sample.Owner.parents＃1]; SQL [更新父集OWNER_ID =？ PARENT_ID =？];嵌套異常是org.hibernate.exception.SQLGrammarException：無法插入集合： [sample.Owner.parents＃1]嵌套異常是org.hibernate.exception.SQLGrammarException：無法插入集合：[sample.Owner.parents＃1 ]

如果我將InheritanceType更改爲JOINED，它工作正常。任何想法爲什麼它試圖堅持父抽象類而不是孩子特定的？

Answer 1

Hibernate對多態關聯表每類層次結構是雙向的（2.2.4.1. Table per class）：

public class Owner { 
    @OneToMany(mappedBy = "owner") 
    private Set<Parent> parents; 
    ... 
} 

public clas Parent { 
    ... 
    @ManyToOne 
    @JoinColumn(name = "OWNER_ID") 
    private Owner owner; 
    ... 
}