DjangoORM一對多&多對多操作

簡要說明

通過操作對象的方式操作數據庫

詳細步驟

models.py的結構是：

如果models.py中外鍵定義沒有寫 related_name=’student_teacher’, 可以直接用

studentList = teacher.student_teacher.all() 可以改寫成：

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))

數據庫一對多的操作：

查找：

方法一：

通過Student表來查：

查找Student表中，teacher_id為1的老師名稱

studentList = Student.objects.all()

模板中使用:

student.teacher.name來獲取外鍵的name屬性值

方法二:

通過Teacher表來查：

teacher = Teacher.objects.get(id = 1) #先查到id 為1 的teacher
studentList = teacher.student_teacher.all() #通過外鍵查到studentlist

新增

方法一：

通過teacher得到student_set來創建
teacher.student_set.create(name = "tom",...)


方法二：

創造一個student對象，添加到teacher的student_set屬性中
student = Student(name = "tom",....)
teacher.student_set.add(student)

修改

只刪除student

 
 
 
         

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

刪除和該teacher相關的所有student

 
 
 
         

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

數據庫多對多操作：

 
 
 
         

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

來自為知筆記(Wiz)