DjangoORM一对多&多对多操作

简要说明



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()

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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()

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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()

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来自为知笔记(Wiz)