Warning: file_get_contents(/data/phpspider/zhask/data//catemap/9/java/314.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181
Java JPA:反向级联删除_Java_Jpa - Fatal编程技术网

Java JPA:反向级联删除

Java JPA:反向级联删除,java,jpa,Java,Jpa,此代码毫无例外地运行,但当我下次加载p时,会附加一个新的子级。如果希望从两侧执行删除操作,则需要定义父级和子级之间的双向关系: Parent p = new Parent(); Child c = new Child(); p.children.add(c); EntityManager.persist(p); EntityManager.persist(c); EntityManager.remove (c); //在父级中 @OneToMany(cascade=CascadeType.

此代码毫无例外地运行,但当我下次加载p时,会附加一个新的子级。

如果希望从两侧执行删除操作,则需要定义父级
和子级
之间的双向关系:

Parent p = new Parent();
Child c = new Child();
p.children.add(c);

EntityManager.persist(p);
EntityManager.persist(c);

EntityManager.remove (c);
//在父级中
@OneToMany(cascade=CascadeType.REMOVE,mappedBy=“parent”)
List children=new ArrayList();
//在儿童时期
@许多酮
父母;
Parent p = new Parent();
Child c = new Child();
p.children.add(c);

EntityManager.persist(p);
EntityManager.persist(c);

EntityManager.remove (c);
// in Parent
@OneToMany(cascade=CascadeType.REMOVE, mappedBy="parent")
List<Item> children = new ArrayList<Child>();

// in Child
@ManyToOne
Parent parent;