app/views.py
from django.db.models import Avg, Sum, Count, Max, Min, F, Q
from django.http import HttpResponse
from django.shortcuts import render
from app.models import Student, StudentInfo, Grade, Course
def hello(request):
return HttpResponse('hello world')
def add_stu(request):
if request.method == 'GET':
# 第一种方式: 新增学生信息
# stu = Student()
# stu.s_name = '小明'
# stu.age = 29
# stu.save()
# 第二种方式: create()
# objects: 管理器
for i in range(10):
Student.objects.create(s_name='小花' + str(i), age=20 + i)
# flask中使用flask-sqlalchemy，Student.query
# tornado中使用sqlalchemy，session.query(Student).filter
# Django中使用自带的ORM，Student.objects
return HttpResponse('创建成功')
def del_stu(request):
if request.method == 'GET':
# 实现删除功能
# filter(字段=值)
# 删除单条数据
stu = Student.objects.filter(s_name='小明').first()
stu.delete()
# 删除多条数据
Student.objects.filter(s_name='小花').delete()
return HttpResponse('删除成功')
def update_stu(request):
if request.method == 'GET':
# 第一种方式: 修改数据， save()
# stu = Student.objects.filter(s_name='小花').first()
# stu.age = 19
# stu.save()
# 第二种方式: update()
Student.objects.filter(s_name='小花').update(age=18, s_name='小强')
return HttpResponse('修改数据')
def sel_stu(request):
if request.method == 'GET':
# 查询数据
stu = Student.objects.filter(s_name='小明').all()
# stu的结果类型为QuerySet，取其中的数据，first()，last()，[下标]
# flask: get(主键值) ，查询结果为获取主键所在行的对象
# django: get(任何条件)，查询满足条件的结果即可
stu = Student.objects.get(s_name='小明')
print(stu)
stu = Student.objects.filter(s_name='小明').first()
print(stu)
# django: get(条件)，查询条件必须查找到结果，
# 如果查询不到结果则报错‘DoesNotExist’
# stu = Student.objects.get(id=1000)
# 如果查询结果超过一个对象，则报错‘MultipleObjectsReturned ’
# stu = Student.objects.get(age=23)
# 总结: get()： 查询条件必须成立且结果只能有一个
print(stu)
# filter()过滤满足条件， exclude()过滤不满足条件
stus = Student.objects.exclude(age=23).all()
print(stus)
# count()统计多少条数据
stus = Student.objects.all()
print(len(stus))
stus = Student.objects.all().count()
print(stus)
# 排序, 升序order_by('id') 降序order_by('-id')
stus = Student.objects.all().order_by('-id')
stus = Student.objects.all().order_by('id')
print(stus)
# values(): 序列化，将对象的属性转化为字典格式数据
stus = Student.objects.all().values('s_name', 'age')
print(stus)
# contains，字段__contains = ’值‘
stus = Student.objects.filter(s_name__contains='花').all()
stus = Student.objects.filter(s_name__startswith='花').all()
print(stus)
stus = Student.objects.filter(s_name__endswith='9').all()
print(stus)
# in, pk=id
stus = Student.objects.filter(id__in=[1, 2, 3, 4, 5, 6, 7]).all()
stus = Student.objects.filter(pk__in=[1, 2, 3, 4, 5, 6, 7]).all()
print(stus)
# 大于23，gt,gte,lt,lte
stus = Student.objects.filter(age__gt=23).all()
stus = Student.objects.filter(age__gte=23).all()
print(stus)
# 聚合，Count(), Max(), Min()
# select s_name, max(chengji) from student;
# from django.db.models import Avg
stus = Student.objects.all().aggregate(Avg('age'))
print(stus)
# 查询语文成绩大于数据成绩的学生信息
# sql: select * from student where yuwen > math;
stus = Student.objects.filter(yuwen__gt=F('math'))
stus = Student.objects.filter(yuwen__gt=F('math') + 10)
print(stus)
# Q,且，或，非
stus = Student.objects.filter(s_name__contains='花', age=23).all()
# 或者条件
stus = Student.objects.filter(Q(s_name__contains='花') | Q(age=23)).all()
# ~非
stus = Student.objects.filter(~Q(s_name__contains='花')).all()
stus = Student.objects.exclude(s_name__contains='花').all()
print(stus)
return HttpResponse('查询数据成功')
def add_stu_info(request):
if request.method == 'GET':
# 向拓展表中添加信息
stu_info = StudentInfo()
stu_info.phone = '13551370671'
stu_info.save()
# 拓展表主键id值
s_id = stu_info.id
stu= Student.objects.filter(s_name='小明').first()
# 第一种写法: 学生对象.OneToOneFiled字段 = 关联对象
stu.stuinfo = stu_info
# 第二种写法: 学生对象.OneToOneFiled字段_id = 关联对象.id
stu.stuinfo_id = stu_info.id
stu.save()
return HttpResponse('添加拓展表信息')
def sel_stuinfo_by_stu(request):
if request.method == 'GET':
# 通过学生信息找拓展表信息
stu = Student.objects.get(s_name='小明')
# StudentInfo.objects.get(pk=stu.stuinfo_id)
# 学生对象.OneToOneFiled字段
stu.stuinfo
return HttpResponse('获取拓展表信息成功')
def sel_stu_by_info(request):
if request.method == 'GET':
# 通过拓展表中的手机号码13551370673找学生信息
stuinfo = StudentInfo.objects.filter(phone='13551370673').first()
# stu = Student.objects.filter(stuinfo=stuinfo)
# stu = Student.objects.filter(stuinfo_id=stuinfo.id)
# print(stu)
# 拓展表对象.关联的模型名称小写
stu = stuinfo.student
# 定义related_name参数，拓展表对象.related_name值
stu = stuinfo.stu
print(stu)
return HttpResponse('通过拓展表信息查询学生表信息')
def add_grade(request):
if request.method == 'GET':
# 添加班级信息，并给学生分配班级
names = ['Python班级', 'Java班级', 'Php班级', 'C++班级']
for name in names:
if not Grade.objects.filter(g_name=name).exists():
Grade.objects.create(g_name=name)
# 分配班级
stus = Student.objects.filter(pk__in=[1, 2, 3, 4, 5, 6]).all()
g = Grade.objects.filter(g_name='Python班级').first()
for stu in stus:
stu.grade = g
# stu.grade_id = g.id
stu.save()
return HttpResponse('添加班级和学生信息')
def sel_grade_by_stu(request):
if request.method == 'GET':
# 通过学生查询班级信息
stu = Student.objects.filter(s_name='小明').first()
g = stu.grade
print(g)
# 班级查询学生
stus = g.student_set.all()
stus = g.stu.all()
return HttpResponse('通过学生查询班级成功')
def add_course(request):
if request.method == 'GET':
# 添加课程信息
names = ['大学语文', '日语', '数电', '模电', '物理', '线代']
for name in names:
cou = Course()
cou.c_name = name
cou.save()
return HttpResponse('创建课程成功')
def sel_cou_by_stu(request):
if request.method == 'GET':
# 查询id为1的学生所选择的课程信息
stu = Student.objects.get(pk=1)
# 学生查询课程
stu.course
# 课程查询学生
cou = Course.objects.get(pk=1)
cou.student_set.all()
cou.stu.all()
return HttpResponse('多对多的查询成功')
def add_del_stu_cou(request):
if request.method == 'GET':
# 增删中间表信息
# 给小明分配‘日语’，‘数电’，‘模电’
stu = Student.objects.filter(s_name='小明').first()
cou1 = Course.objects.get(c_name='日语')
cou2 = Course.objects.get(c_name='数电')
cou3 = Course.objects.get(c_name='模电')
# 新增中间表数据
# stu.course.add(cou1)
# stu.course.add(cou2)
# stu.course.add(cou3)
# cou1.stu.add(学生对象)
# 删除中间表数据
stu.course.remove(cou2)
stu.course.remove(cou3)
return HttpResponse('操作中间表信息成功')
def on_delete_stu(request):
if request.method == 'GET':
# 演示删除，on_delete参数的效果
stuinfo = StudentInfo.objects.get(id=1)
stuinfo.delete()
# models.CASCADE 表示:主键所在行的数据被删，外键所在行的数据也会被删
# models.PROTECT 表示: 主键有对应的外键数据时，不让删除主键的数据
# models.SET_NULL 表示: 主键删除，外键置空
return HttpResponse('on_delete演示成功')
def index(request):
if request.method == 'GET':
# TODO: render(request)中的request后面讲
stus = Student.objects.all()
content_h2 = 'hello world
'
return render(request,
'index.html',
{'students': stus, 'content_h2': content_h2})
def params(request, id):
if request.method == 'GET':
return HttpResponse('id:%s' % id)
def str_params(request, name):
if request.method == 'GET':
return HttpResponse('name:%s' % name)
def uid_params(request, uid):
if request.method == 'GET':
# uuid.uuid4()
return HttpResponse('uid:%s' % uid)
def path_params(request, ph):
if request.method == 'GET':
return HttpResponse('path:%s' % ph)
def year_parmas(request, day, year, month):
if request.method == 'GET':
return HttpResponse('%s年%s月%s日' % (year, month, day))
app/urls.py
from django.urls import path, re_path
from app.views import *
urlpatterns = [
path('hello/', hello),
path('add_stu/', add_stu),
path('del_stu/', del_stu),
path('update_stu/', update_stu),
path('sel_stu/', sel_stu),
path('add_stu_info/', add_stu_info),
path('sel_stuinfo_by_stu/', sel_stuinfo_by_stu),
path('sel_stu_by_info/', sel_stu_by_info),
path('add_grade/', add_grade),
path('sel_grade_by_stu/', sel_grade_by_stu),
path('add_course/', add_course),
path('sel_cou_by_stu/', sel_cou_by_stu),
path('add_del_stu_cou/', add_del_stu_cou),
path('on_delete_stu/', on_delete_stu),
path('index/', index),
# 接收传参数的路由url
path('params//', params),
path('str_params//', str_params),
path('uuid_params//', uid_params),
path('path_params//', path_params),
# re_path 替代2.0一下版本中的url
re_path('year_params/(\d+)/(\d+)/(\d+)/', year_parmas),
# ?P\d+
re_path('p_params/(?P\d+)/(?P\d+)/(?P\d+)/', year_parmas),
]
app/models.py
from django.db import models
class Article(models.Model):
# 模型中可不用定义自增的id主键，迁移时会自动创建
# 指定title字段，长度为10，且不能为空
title = models.CharField(max_length=10, null=False)
desc = models.CharField(max_length=100, null=True)
class Meta:
# 指定表明
db_table = 'article'
class StudentInfo(models.Model):
address = models.CharField(max_length=50, null=True)
phone = models.CharField(max_length=11, null=True)
class Meta:
db_table = 'stu_info'
class Grade(models.Model):
g_name = models.CharField(max_length=10, unique=True, null=False)
class Meta:
db_table='grade'
class Course(models.Model):
c_name = models.CharField(max_length=10, unique=True, null=False)
class Meta:
db_table = 'course'
class Student(models.Model):
# 长度为10，且唯一不能为空的姓名s_name字段
s_name = models.CharField(max_length=10, unique=True, null=False)
age = models.IntegerField(default=18)
# auto_now_add: 表示第一次创建数据时，自动默认为当前创建的时间
create_time = models.DateTimeField(auto_now_add=True)
# auto_now: 表示修改时，自动更新为修改的时间
operate_time = models.DateTimeField(auto_now=True)
is_delete = models.BooleanField(default=0)
# 定义浮点数总长度3为，小数点后1位
yuwen = models.DecimalField(max_digits=3, decimal_places=1, null=True)
math = models.DecimalField(max_digits=3, decimal_places=1, null=True)
# 一对一: 定义在关联的两个模型中的任何一方都可以
stuinfo = models.OneToOneField(StudentInfo, related_name='stu', on_delete=models.SET_NULL, null=True)
# 一对多: 定义在’多‘的一方
grade = models.ForeignKey(Grade, related_name='stu', on_delete=models.CASCADE, null=True)
# 多对多
course = models.ManyToManyField(Course, related_name='stu')
# TimeFiled
# DateField
# ImageField
# TextField
# DecimalField: 5位数，小数点占两位， 999.99
# AutoField
# FloatField
class Meta:
db_table = 'student'