java - JPA CascadeType.REMOVE 不删除关系的子级

Question

在我的项目中，我有下面报告的类，并具有双向关系映射。当我尝试删除关系的父对象(在我的例子中为 DataProvider)时，主对象将被删除，而子对象不会被删除。我还已经测试了其他几种注释组合，但似乎都不起作用(orphanRemoval、@ElementDependent、Optional = false，...)。

删除是通过如下查询完成的:

Query q = em.createQuery("DELETE FROM DataProvider dp WHERE ... ");
q.executeUpdate(); 

有人可以提出建议吗？

@Entity(name = "DataProvider")
public class DataProviderImpl implements DataProvider {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    private String name;
    // ...

    @OneToMany(targetEntity=RestMethodImpl.class, fetch=FetchType.LAZY, mappedBy="dataProvider", cascade={CascadeType.PERSIST,CascadeType.REMOVE})
    private List<RestMethod> methods;


    public DataProviderImpl() {
        super();
        this.id = 0;
    }

    @Override
    public int getId() {
        return id;
    }
    @Override
    public void setId(int id) {
        this.id = id;
    }
    @Override
    public String getName() {
        return name;
    }
    @Override
    public void setName(String name) {
        this.name = name;
    }
    @Override
    public List<RestMethod> getMethods() {
        return methods;
    }
    @Override
    public void setMethods(List<RestMethod> methods) {
        this.methods = methods;
    }
}

.

public interface DataProvider {
    public int getId();
    public void setId(int id);
    public String getName();
    public void setName(String name);
    public List<RestMethod> getMethods();
    public void setMethods(List<RestMethod> methods);
}   

.

@Entity(name = "RestMethod")
public class RestMethodImpl implements RestMethod {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    private String nickname;
    // ...

    @ManyToOne(targetEntity=DataProviderImpl.class, fetch=FetchType.LAZY)
    @JoinColumn(name="dataProviderId")
    private DataProvider dataProvider;

    public RestMethodImpl() {
        super();
        this.id = 0;
    }

    @Override
    public int getId() {
        return id;
    }
    @Override
    public void setId(int id) {
        this.id = id;
    }
    @Override
    public String getNickname() {
        return nickname;
    }
    @Override
    public void setNickname(String nickname) {
        this.nickname = nickname;
    }
    @Override
    public DataProvider getDataProvider() {
        return dataProvider;
    }
    @Override
    public void setDataProvider(DataProvider dataProvider) {
        this.dataProvider = dataProvider;
    }
}

.

public interface RestMethod  {
    public int getId();
    public void setId(int id);
    public String getNickname();
    public void setNickname(String nickname);
    public DataProvider getDataProvider();
    public void setDataProvider(DataProvider dataProvider);
}

.

Answer 1

感谢 @Smutje 链接，我将查询更改为以下内容(有效):

Iterator itr = itemsToDelete.iterator();
int deleted = 0;
while(itr.hasNext()) {
    em.remove(itr.next());
    deleted++;
}

不幸的是，批量删除可能不是很快，但至少对于简单的删除查询，它可以正确级联。