[英]How to define a unidirectional OneToMany JPA relationship without any cascade?
当我试图拯救人时,它既不会保存任何人也不会保存任何东西。 我不想保存或更新City对象。 我只想更新/删除joinColumn。 有没有办法做到这一点?
Person person = new Person();
person.setCities(...);
personDAO.save(person);
public class Person{
@OneToMany(fetch = FetchType.EAGER)
@JoinColumn(name = "city_id")
private List<City> cities;
}
public class City{
@Id
@Column(name = "city_id")
@GeneratedValue(generator = "system-uuid")
@GenericGenerator(name = "system-uuid", strategy = "org.hibernate.id.UUIDGenerator")
private String cityId;
}
首先在City端定义@ManyToOne映射:
@ManyToOne
@JoinColumn(name = "person_id")
private Person person;
然后添加mappedBy
属性并删除@JoinColumn:
@OneToMany(fetch = FetchType.EAGER, mappedBy = "person")
private List<City> cities;
当您保存/更新时,您必须在依赖项的两侧设置实体:
Person person = new Person();
person.setCities(...);
for(City city: cities){
city.setPerson(person);
}
personDAO.save(person);
同样适用于删除..您必须删除双方的实体引用。
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