day04-Django和数据库的应用

views.py

from django.db.models import *
from django.shortcuts import render
#引入学生student模型
from app.models import  Student,StuInfo
from django.http import HttpResponse


def add_stu(request):
    """
    #向数据库中的student表中插入数据
    stu=Student()
    stu.name="小明"
    #向数据库中插入数据
    stu.save()
    """
    #学生类Student===>多个对象=======>写入数据（名字xx，年龄xx，性别x）
    Student.objects.create(name="小明",gender=0,age=19)
    Student.objects.create(name="小花", age=20)
    Student.objects.create(name="林平之", age=28)
    Student.objects.create(name="令狐冲", age=30)
    Student.objects.create(name="任盈盈", age=18,gender=0)
    #查询语文成绩比数学成绩大的学生信息
    stus = Student.objects.filter(yuwen__gt=F("nath"))
    #__gt大于=====>yuwen__gt=F("nath") 
    #F后面是指定哪个对象来比较 
    


    return HttpResponse("创建成功")


def del_stu(request):
    #实现删除
    #sql:delete from student where name="大锤"
    #1.查询name = "大锤"的信息
    Student.objects.filter(name='王大锤').delete()
    return HttpResponse("删除成功")


def up_stu(request):
    """
    #实现更新
    #第一种方式
    stus=Student.objects.filter(name="小明")
    stu = stus[0]
    stu.name="大明"
    stu.save()
    return HttpResponse("更新成功")
    """
    stu= Student.objects.filter(name="小明").first()
    stu.name = "大明"
    stu.save()
    Student.objects.filter(name="大明").update(name="丽歌")


def sel_stu(request):


    #查询
    stus = Student.objects.filter(age=18)
    stus = Student.objects.all()
    #查询
    # get()：方法是获取唯一的满足条件的对象，且查询的条件必须存在
    # 如果查询条件不存在，则报错
    # 如果查询的结果对于一个，则报错
    stu = Student.objects.get(name="大明")
    #获取不叫小明的学生
    stus = Student.objects.exclude(name="大明")#取反的操作
    #查询年龄是18的女生
    stus = Student.objects.filter(age=18,gender=0)

    #排序 order_by
    #降序 -age 在sql中 age desc
    #升序 age  在sql中 age asc
    stus = Student.objects.all().order_by("-age")
    #获取对象的值
    stus_value = Student.objects.all().values()
    #判断name=妲己的学生存不存在
    stu = Student.objects.filter(name="妲己")
    #查询姓名中包含"大"的学生信息
    #contains:大小写敏感
    #icontains:大小写不敏感
    #类似于like"%小%"
    stus = Student.objects.filter(name__contains="小")
    #类似于like"%小"
    stus = Student.objects.filter(name__endswith="小")
    #类似于like"小%"
    stus = Student.objects.filter(name__startswith="小")
    #sql select = from xxx where id in
    stus = Student.objects.filter(id__in=[1,2,3])
    stus = Student.objects.filter(pk__in=[1,2,3])
    #大于:__gt
    #小于：__lt
    stus = Student.objects.filter(age__lt=19)#小于

    #聚合aggregate
    avg_age = Student.objects.all().aggregate(Avg("age"))
    print(avg_age)
    sum_age = Student.objects.all().aggregate(Sum("age"))
    print(sum_age)
    #或者条件、非条件、并且条件
    #查询age = 18或者gender = 1的学生信息
    #Q()
    # from django.db.models import Q
    stus = Student.objects.filter(Q(age=18),Q(gender=1))
    stus = Student.objects.filter(Q(age=18)| Q(gender=1))
    stus = Student.objects.filter(Q(age=18) & Q(gender=1))
    stus = Student.objects.filter(~Q(age=18)|Q(gender=1))
    # 获取学生的姓名
    stus_names = [stu.name for stu in stus]
    # 查询语文成绩比数学成绩大的学生信息
    stus = Student.objects.filter(yuwen__gt=F("nath"))
    # 查询语文成绩比数学成绩大10分的学生信息
    stus = Student.objects.filter(yuwen__gt=F("nath")+10)

    return  HttpResponse(stus_names)

def add_stu_info(request):
    s_info = Student()
    s_info.phone = "12134123123"
    s_info.address = "天府新区"
    s_info.stu = Student.objects.get(pk=5)
    s_info.save()
    return  HttpResponse("创建拓展信息")

    #通过学生去查学生信息

def sel_info_by_stu(request):
    #第一种方法
    stu = Student.objects.filter(name="大明").first()#通过学生类找到名字叫大明这个对象，可能有多个，first取到的是第一个
    #通过学生的信息表类找到与之
    stu_info = StuInfo.objects.filter(stu_id=stu.id).first()
    phone = stu_info.phone
    #第二种方法（反向查询）
    stu_info = stu.stuinfo
    phone = stu_info.phone

    return HttpResponse(phone)

def sel_stu_by_info(request):
    stu_info = StuInfo.objects.get(phone="12134123123")
    stu = stu_info.stu
    return HttpResponse('通过拓展表查询学生信息')

models.py

from django.db import models


class Student(models.Model):
    name = models.CharField(max_length=10,unique=True)
    age = models.IntegerField(default=18)
    gender = models.BooleanField(default=1)
    #auto_now_add:创建数据时，默认create_time字段为当前时间
    create_time = models.DateTimeField(auto_now_add=True,null=True)
    #auto_now:修改数据，每次update学生信息时，修改该字段的时间为当前时间

    operate_time = models.DateTimeField(auto_now=True,null=True)
    yuwen = models.DecimalField(max_digits=3,decimal_places=1, null=True)
    nath = models.DecimalField(max_digits=3,decimal_places=1, null=True)


    class Meta:
        db_table = "student"


class StuInfo(models.Model):
    phone = models.CharField(max_length=11)
    address = models.CharField(max_length=100)
    #OneToOneField等价于Forieignkey,且约束nuique=True
    stu = models.OneToOneField(Student)

    class Meta:
        db_table = "grade"