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()

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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)