DjangoORM一对多&多对多操作

简要说明

通过操作对象的方式操作数据库

详细步骤

models.py的结构是：

如果models.py中外键定义没有写 related_name=’student_teacher’, 可以直接用

studentList = teacher.student_teacher.all() 可以改写成：

teacher = Teacher.objects.get(id = 1)

studentList = teacher.student_set.all()

============================================================================================

from myblog.models import Student,Teacher

def student_list(request):

t = loader.get_template("student_list.html")

#studentList = Student.objects.all()

teacher = Teacher.objects.get(id = 1)

studentList = teacher.student_teacher.all()

c = Context({"studentList":studentList})

return HttpResponse(t.render(c))

数据库一对多的操作：

查找：

方法一：

通过Student表来查：

查找Student表中，teacher_id为1的老师名称

studentList = Student.objects.all()

模板中使用:

student.teacher.name来获取外键的name属性值

方法二:

通过Teacher表来查：

teacher = Teacher.objects.get(id = 1) #先查到id 为1 的teacher
studentList = teacher.student_teacher.all() #通过外键查到studentlist

新增

方法一：

通过teacher得到student_set来创建
teacher.student_set.create(name = "tom",...)


方法二：

创造一个student对象，添加到teacher的student_set属性中
student = Student(name = "tom",....)
teacher.student_set.add(student)

修改

只删除student

 
 
 

 teacher = Teacher.objects.get(id = 1)
  
  
  
 student = teacher.student_set.get(id = 1)
  
  
  
 student.delete()
 
 
 

删除和该teacher相关的所有student

 
 
 

 teacher = Teacher.objects.get(id = 1)
  
  
  
 student = teacher.student_set.get(id = 1) 
  
  
  
 student.teacher.delete()
 
 
 

数据库多对多操作：

 
 
 

 group = Group.objects.get(id = 1)
  
  
  
 studentList = group.members.all()
  
  
  
 groupList = student.group_set.all()
  
  
  
 MemberShip(group = newGroup, student=newStudent).save()
 
 
 

来自为知笔记(Wiz)