JPA：当父实体被删除时，子实体仍然存在
Customer 实体中的客户实体（父实体）
@Entity
public class Customer {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
@OneToMany(mappedBy="customer", cascade=CascadeType.ALL)
private List<Facility> facilities;
//Setter and Getter for name and facilities
public void addFacility(Facility facility){
if(this.facilities == null){
this.facilities = new ArrayList<Facility>();
}
this.facilities.add(facility);
facility.setCustomer(this);
}
}
设施实体（子实体）
@Entity
public class Facility {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
@ManyToOne
@JoinColumn(name="CUSTOMER_FK")
private Customer customer;
private String name;
//Setter and Getter, equals and hashcode
...
}
，我使用 CascadeType.ALL，但是当我删除客户时，关联的设施仍然存在。 删除 customer
Query query = em.createNamedQuery("Customer.delete");
query.setParameter("id", customerId);
query.executeUpdate();
我按以下位置
@NamedQuery(name="Customer.delete", query="delete from Customer c where c.id = :id")
Customer Entity (Parent Entity)
@Entity
public class Customer {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
@OneToMany(mappedBy="customer", cascade=CascadeType.ALL)
private List<Facility> facilities;
//Setter and Getter for name and facilities
public void addFacility(Facility facility){
if(this.facilities == null){
this.facilities = new ArrayList<Facility>();
}
this.facilities.add(facility);
facility.setCustomer(this);
}
}
Facility Entity (Child Entity)
@Entity
public class Facility {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
@ManyToOne
@JoinColumn(name="CUSTOMER_FK")
private Customer customer;
private String name;
//Setter and Getter, equals and hashcode
...
}
in Customer entity, I use CascadeType.ALL, however when I remove a customer, the associated facilities are still there. I delete customer by
Query query = em.createNamedQuery("Customer.delete");
query.setParameter("id", customerId);
query.executeUpdate();
where
@NamedQuery(name="Customer.delete", query="delete from Customer c where c.id = :id")
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评论（2）
根据 JPA 规范，批量删除操作不会级联：
如果您想从级联中受益，请加载实体，然后对其调用 EntityManager#remove(Object) 。
Bulk delete operations are not cascaded, per JPA specification:
If you want to benefit from cascading, load the entity and then call
EntityManager#remove(Object)on it.尝试使用：
@Inject
EntityManager em;
客户客户 =...;em.remove(customer);
这总是级联操作。
Try with:
@InjectEntityManager em;
Customer customer =...;em.remove(customer);
This always cascades operations.