Question

我有一个部门实体,关系如下:

Many departments can be in one parent department:

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

www.un.org/Depts/DGACM/index_spanish.htm 1个上级部门可以有many Province:

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

接下来,我想执行: 当Idelete a department时,ik_jun_department_id para amount of allchildren of this department is set to null。任何关于如何这样做的想法?

Answer 1

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();

随行,你只能设法删除<条码><部门/代码>。

Answer 2

与日本宇宙开发公司合作,在母体Entity上,你可能拥有类似的东西。

@OneToMany(mappedBy="parent", cascade={CascadeType.PERSIST})
Collection<Child> children;

为了避免重复“一成不变的法典”和“安乐”;在“母体编码”中执行关于父母分离的违反诚信的例外规定。

@PreRemove
private void preRemove() {
   children.forEach( child -> child.setParent(null));
}

Answer 3

Just code it:

for (Department child : parent.getChildren()) {
    child.setParentDepartment(null);
}
session.delete(parent);

友情链接