在@OneToMany的hibernate中删除set null [英] On delete set null in hibernate in @OneToMany

问题描述

我有一个部门实体，其关系如下：

1. 许多部门可以在一个家长部门中：
   
   

     @ManyToOne 
    @JoinColumn（name =ik_parent_department_id ）
   私人部门parentDepartment; 
     




2. 一个父部门 / strong>：
   
   

     @OneToMany（mappedBy =parentDepartment）
    private Set< Department> children = new HashSet< Department>（0）; 
     

我想实现下一个：When我删除部门，然后部门的所有子女的 ik_parent_department_id 参数已设置为 null 。任何想法如何做到这一点？

解决方案

您必须设置孩子的 ik_parent_department_id 显式为null。

 部门parentDepartment =（部门）session.load（Department.class，id）; 
 session.delete（parentDepartment）; 
 for（Department child：parentDepartment.getChildren（））{
 child.setParentDepartment（null）; 
} 
 session.flush（）; 
  

通过级联，您只能设法删除子部门。

I have a Department entity which relations are as follows:

1. Many departments can be in one parent department:

   @ManyToOne
   @JoinColumn(name = "ik_parent_department_id")
   private Department parentDepartment;
   

2. One parent department can have many departments:

   @OneToMany(mappedBy = "parentDepartment")
   private Set<Department> children = new HashSet<Department>(0);
   

And I want to implement the next: When I delete a department, then the ik_parent_department_id parameter of all children of this department is set to null. Any ideas how to do that?

解决方案

You'll have to set the children's ik_parent_department_id to null explicitly.

Department parentDepartment = (Department) session.load(Department.class, id);
session.delete(parentDepartment);
for (Department child : parentDepartment.getChildren()){
    child.setParentDepartment(null);
} 
session.flush();

With cascading you would only manage to delete child Departments.

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