Java 从@OneToMany关联中删除child:CascadeType.ALL+;删除=true不工作
我很难把孩子们从一个只有一个家庭的协会中除名。我的实体:Java 从@OneToMany关联中删除child:CascadeType.ALL+;删除=true不工作,java,hibernate,jpa-2.0,Java,Hibernate,Jpa 2.0,我很难把孩子们从一个只有一个家庭的协会中除名。我的实体: @Entity @Table(name = "PERSON") public class PersonEntity extends BaseVersionEntity<Long> implements Comparable<PersonEntity> { ... // bi-directional many-to-one association to Project @OneToMany(cascade
@Entity
@Table(name = "PERSON")
public class PersonEntity extends BaseVersionEntity<Long> implements Comparable<PersonEntity>
{
...
// bi-directional many-to-one association to Project
@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "person", orphanRemoval = true)
private final Set<ProjectEntity> projects = new HashSet<ProjectEntity>();
...
@Entity
@Table(name = "PROJECT")
public class ProjectEntity extends BaseVersionEntity<ProjectPK>
{
@EmbeddedId
private ProjectPK id;
...
// bi-directional many-to-one association to UdbPerson
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "PERSON_ID", nullable = false, insertable = false, updatable = false)
private PersonEntity person;
...
@Embeddable
public class ProjectPK implements Serializable
{
// default serial version id, required for serializable classes.
private static final long serialVersionUID = 1L;
@NotNull
@Column(name = "PERSON_ID")
private Long personId;
...
这是可行的,但我认为这不是正确的方法:
for (Iterator<ProjectEntity> iterator = personEntity.getProjects().iterator(); iterator.hasNext();)
{
ProjectEntity projectEntity = iterator.next();
projectDao.deleteEntity(projectEntity);
iterator.remove();
}
for(Iterator Iterator=personEntity.getProjects().Iterator();Iterator.hasNext();)
{
ProjectEntity=iterator.next();
projectDao.deleteEntity(projectEntity);
iterator.remove();
}
我做错了什么
谢谢Jonny关联是双向的,双向关联的拥有方是没有mappedBy属性的一方。这意味着在这种情况下,拥有方是项目方
Hibernate只考虑拥有方是否知道关联存在。这意味着要断开人员与项目之间的关联,必须在项目中将人员设置为
null
谢谢你,这就成功了。下面是代码:for(Iterator Iterator=personEntity.getProjects().Iterator();Iterator.hasNext();){ProjectEntity ProjectEntity=Iterator.next();ProjectEntity.setPerson(null);Iterator.remove();}
person不能为null怎么办?@IgorG。如果person不能为null,那么删除关联是没有意义的。这个答案是错误的。您正在寻找的真正答案(并允许您保留非空约束)可以在此处找到:@JamesD:您链接到的答案与我的答案完全相同。您需要添加一个mappedBy属性来声明关联的拥有方和contact.setAccount(null)代码>。
for (Iterator<ProjectEntity> iterator = personEntity.getProjects().iterator(); iterator.hasNext();)
{
ProjectEntity projectEntity = iterator.next();
projectDao.deleteEntity(projectEntity);
iterator.remove();
}