饮冰三年-人工智能-Python-24 Django ORM增删改查

一：首先使用默认的sqlite3创建表

---

　　1：现在在models.py中添加表模型

from django.db import models

# Create your models here.
class Book(models.Model):
    name=models.CharField(max_length=20)
    price = models.IntegerField()
    pub_date=models.DateField()

models.py

　　2：在Teminal中通过命令创建表

　　python manage.py makemigrations ----------该命令执行后会在migrations中创建0001_initial.py中生成文件　

　　python manage.py migrate　　----------该命令执行后会在数据库中生成数据表

至此，数据库创建成功

二：使用Mysql创建表

---

　　1：修改配置表

"""
Django settings for Django_ORM project.

Generated by 'django-admin startproject' using Django 2.1.4.

For more information on this file, see
https://docs.djangoproject.com/en/2.1/topics/settings/

For the full list of settings and their values, see
https://docs.djangoproject.com/en/2.1/ref/settings/
"""

import os

# Build paths inside the project like this: os.path.join(BASE_DIR, ...)
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))

# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/2.1/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = '(%h695j&g^4s(@&hk9#66xye6nrv=y9hr*(1va58(^j%_zmlzw'

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True

ALLOWED_HOSTS = []

# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'app01.apps.App01Config',
]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'Django_ORM.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [os.path.join(BASE_DIR, 'templates')]
        ,
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

WSGI_APPLICATION = 'Django_ORM.wsgi.application'

# Database
# https://docs.djangoproject.com/en/2.1/ref/settings/#databases

# DATABASES = {
#     'default': {
#         'ENGINE': 'django.db.backends.sqlite3',
#         'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
#     }
# }
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'Django_ORM',    #你的数据库名称
        'USER': 'root',   #你的数据库用户名
        'PASSWORD': '12qwaszx!@QWASZX', #你的数据库密码
        'HOST': '', #你的数据库主机，留空默认为localhost
        'PORT': '', #你的数据库端口

    }

}

# Password validation
# https://docs.djangoproject.com/en/2.1/ref/settings/#auth-password-validators

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]

# Internationalization
# https://docs.djangoproject.com/en/2.1/topics/i18n/

LANGUAGE_CODE = 'en-us'

TIME_ZONE = 'UTC'

USE_I18N = True

USE_L10N = True

USE_TZ = True

# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/2.1/howto/static-files/

STATIC_URL = '/static/'

Setting.py

　　2：修改Django_ORM下面的__init__.py文件 （python的数据库驱动引擎，把默认的MySQLdb()替换成pymysql）

　　　　如果事先没有安装pymysql模块 可通过 pip install pymysql命令安装

import pymysql
# （python的数据库驱动引擎，把默认的MySQLdb()替换成pymysql）
pymysql.install_as_MySQLdb()

__init__.py

　　3：继续执行以下命令

　　python manage.py makemigrations ----------该命令执行后会在migrations中创建0001_initial.py中生成文件　

　　python manage.py migrate　　----------该命令执行后会在数据库中生成数据表

　　至此，数据表创建成功

三、通过orm对表进行增删改查

---

　　在settings加上日志记录部分，就可以方便的看出每条操作所执行的SQL语句了　　

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'handlers': {
        'console':{
            'level':'DEBUG',
            'class':'logging.StreamHandler',
        },
    },
    'loggers': {
        'django.db.backends': {
            'handlers': ['console'],
            'propagate': True,
            'level':'DEBUG',
        },
    }
}

LOGGING

　　1：创建首页　　

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        *{
           margin: 0px;
           padding: 0px;
        }
        .head{
            line-height: 40px;
            background-color: green;
            color: white;
            text-align: center;
        }
    </style>
</head>
<body>
    <div class="outer">
        <div class="head">标题</div>
        <div class="content">
            <a href="/addbook/">添加书籍</a>
            <a href="/updatebook/">修改书籍</a>
            <a href="/deltebook/">删除书籍</a>
        </div>
        <div></div>
    </div>
</body>
</html>

index.html

　　2：设置对应urls

"""Django_ORM URL Configuration

The `urlpatterns` list routes URLs to views. For more information please see:
    https://docs.djangoproject.com/en/2.1/topics/http/urls/
Examples:
Function views
    1. Add an import:  from my_app import views
    2. Add a URL to urlpatterns:  path('', views.home, name='home')
Class-based views
    1. Add an import:  from other_app.views import Home
    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
Including another URLconf
    1. Import the include() function: from django.urls import include, path
    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
"""
from django.contrib import admin
from django.urls import path
from app01 import views
urlpatterns = [
    path('admin/', admin.site.urls),
    path('index/', views.index,name="index"), #创建首页
    path('addbook/', views.addbook,name="addbook"), #新增书籍
    path('updatebook/', views.updatebook, name="updatebook"),  # 新增书籍
    path('deltebook/', views.deltebook, name="deltebook"),  # 新增书籍
]

urls.py

　　3：views

from django.shortcuts import render,HttpResponse
from app01.models import *
# Create your views here.
def index(request):
    return render(request,"index.html")
def addbook(request):
    # 方式一
    b=Book(name="python",price=80,pub_date="2012-12-12",author="张三")
    b.save()
    # 方式二
    Book.objects.create(name="Linux",price=99,author="李四",pub_date="2011-11-11")
    return HttpResponse("添加成功！")
def updatebook(request):
    # 方式一
    Book.objects.filter(author="李四").update(price=999)
    # 方式二
    b=Book.objects.get(id=2)
    b.price=888
    b.save()
    return HttpResponse("修改成功！")
def deltebook(request):
    Book.objects.filter(id=1).delete()
    return HttpResponse("删除成功！")

views

from django.shortcuts import render,HttpResponse
from app01.models import *
# Create your views here.
def index(request):
    return render(request,"index.html")
def addbook(request):
    # 方式一
    b=Book(name="python",price=,pub_date="2012-12-12",author="张三")
    b.save()
    # 方式二
    Book.objects.create(name="Linux",price=,author="李四",pub_date="2011-11-11")
    return HttpResponse("添加成功！")
def updatebook(request):
    # 方式一
    Book.objects.filter(author="李四").update(price=)
    # 方式二
    b=Book.objects.get(id=)
    b.price=
    b.save()
    return HttpResponse("修改成功！")
def deltebook(request):
    Book.objects.filter(id=).delete()
    return HttpResponse("删除成功！")
def querybook(request):
    # ----------返回的是个集合 <class 'django.db.models.query.QuerySet'>----------
    # bookList=Book.objects.all()# 查询所有结果
    # bookList=Book.objects.all()[:]# 查询结果 支持切片
    # bookList = Book.objects.filter(author='张三')#它包含了与所给筛选条件相匹配的对象
    # bookList = Book.objects.all().exclude(author='张三')#它包含了与所给筛选条件不匹配的对象
    # ----------like------------返回的是个集合 <class 'django.db.models.query.QuerySet'>----------
    # bookList = Book.objects.filter(id__lte=,id__gt=)  # 查询所有结果 <id<=
    # bookList = Book.objects.filter(id__range=[,])  # 查询所有结果 between and
    # bookList = Book.objects.filter(id__in=(,))  # 查询所有结果 in
    # bookList = Book.objects.exclude(id__in=(,))  # 查询所有结果 not in
    # bookList = Book.objects.filter(name__contains="lin")  #
    # bookList = Book.objects.filter(name__icontains="lin")  #  忽略大小写
    # bookList = Book.objects.filter(name__startswith="lin")  #
    # bookList = Book.objects.filter(name__istartswith="lin")  #  忽略大小写
    # bookList = Book.objects.filter(name__endswith="A")  #
    bookList = Book.objects.filter(name__iendswith="A")  #  忽略大小写
    # ----------返回的是个对象 <class 'app01.models.Book'>----------
    # aBook = Book.objects.get(id=) # 返回与所给筛选条件相匹配的对象，返回结果有且只有一个，如果符合筛选条件的对象超过一个或者没有都会抛出错误
    # aBook = Book.objects.first() #  返回第一条记录
    # aBook = Book.objects.last() #  返回最后一条记录
    # ----------对返回结果进行处理----------
    # bookList = Book.objects.all().values("name","author") #只筛选“书名”和“作者”
    # bookList = Book.objects.all().values_list("name", "author") #它与values()非常相似，它返回的是一个元组序列，values返回的是一个字典序列 <QuerySet [('python', '张三'), ('Linux', '李四'), ('Java', '张三2'), ('Linux2', '李四')]>
    # bookList = Book.objects.all().order_by("price","id") #排序
    # bookList = Book.objects.all().reverse()#对查询结果反向排序,貌似没什么用
    # bookList = Book.objects.all().values("author").distinct()#从返回结果中剔除重复纪录
    # num=Book.objects.all().count()# 返回数据库中匹配查询(QuerySet)的对象数量。
    # num = Book.objects.filter(author='张三111').exists()#  如果QuerySet包含数据，就返回True，否则返回False。
    return render(request,"index.html",locals())

查询

四、通过orm对表进行增删改查之一对多

---

from django.shortcuts import render,HttpResponse
from APP2.models import *
# Create your views here.
def index(request):
    return render(request,"index.html")
def addbook(request):
    # 方式一，通过ID保存
    b=Book(name=".net",price=80,pub_date="2012-12-12",publish_id="")
    b.save()
    # 方式二，先获取“出版社”实体，再保存
    pub=Publish.objects.get(id=1)
    Book.objects.create(name="Linux",price=99,pub_date="2011-11-11",publish=pub)
    return HttpResponse("添加成功！")
def updatebook(request):
    # 方式一 更改“清华出版社”下所有书的价格
    Book.objects.filter(publish__name="清华出版社").update(price=999)
    # 方式二 更改id为2的书的出版社名称
    b=Book.objects.filter(id=2)[0].publish
    b.name="新华出版社"
    b.save()
    return HttpResponse("修改成功！")
def deltebook(request):
    Book.objects.filter(publish__name="新华出版社").delete()
    return HttpResponse("删除成功！")
def querybook(request):
    # 获取某出版社出版的书
    # ----------方式1：先获取某出版社--->再获取对应的书----------
    # pu=Publish.objects.filter(name="北京大学出版社")[0]
    # bookList=Book.objects.filter(publish=pu)
    # ----------方式2----------
    # bookList = Publish.objects.get(id=1).book_set.all()
    # ----------方式3-双下划线----------
    bookList = Book.objects.filter(publish__name="北京大学出版社")
    # 练习：查询某书的出版社名称
    publishName =Book.objects.filter(name="python").values_list("publish__name")[0]
    publishName=Publish.objects.filter(book__name="python").values_list("name")[0]
    return render(request,"index.html",locals())

五、通过orm对表进行增删改查之多对多

---

from django.db import models

class Book(models.Model):
    name=models.CharField(max_length=20)
    price = models.IntegerField()
    pub_date=models.DateField()
    # 创建一对多的方法
    publish = models.ForeignKey("Publish",on_delete=models.CASCADE)
    # 创建多对多的方法
    authors=models.ManyToManyField("Author")
class Publish(models.Model):
    name = models.CharField(max_length=32)
    city = models.CharField(max_length=32)

class Author(models.Model):
    name=models.CharField(max_length=32)
    age=models.IntegerField()

多对多

　　

from django.db import models

class Book(models.Model):
    name=models.CharField(max_length=20)
    price = models.IntegerField()
    pub_date=models.DateField()
    # 创建一对多的方法
    publish = models.ForeignKey("Publish",on_delete=models.CASCADE)
    # 创建多对多的方法
    authors=models.ManyToManyField("Author")
class Publish(models.Model):
    name = models.CharField(max_length=32)
    city = models.CharField(max_length=32)

class Author(models.Model):
    name=models.CharField(max_length=32)
    age=models.IntegerField()

models

from django.shortcuts import render,HttpResponse
from django.db.models import Avg,Max,Sum,Min,F,Q
from APP2.models import *
# Create your views here.
def index(request):
    return render(request,"index.html")
def addbook(request):
    # 方式一，通过ID保存
    b=Book(name=".net",price=80,pub_date="2012-12-12",publish_id="")
    b.save()
    # 方式二，先获取“出版社”实体，再保存
    pub=Publish.objects.get(id=1)
    Book.objects.create(name="Linux",price=99,pub_date="2011-11-11",publish=pub)
    return HttpResponse("添加成功！")

def updatebook(request):
    # 方式一 更改“清华出版社”下所有书的价格
    Book.objects.filter(publish__name="清华出版社").update(price=999)
    # 方式二 更改id为2的书的出版社名称
    b=Book.objects.filter(id=2)[0].publish
    b.name="新华出版社"
    b.save()
    return HttpResponse("修改成功！")
def deltebook(request):
    Book.objects.filter(publish__name="新华出版社").delete()
    return HttpResponse("删除成功！")
def querybook(request):
    # 获取某出版社出版的书
    # ----------方式1：先获取某出版社--->再获取对应的书----------
    # pu=Publish.objects.filter(name="北京大学出版社")[0]
    # bookList=Book.objects.filter(publish=pu)
    # ----------方式2----------
    # bookList = Publish.objects.get(id=1).book_set.all()
    # ----------方式3-双下划线----------
    bookList = Book.objects.filter(publish__name="北京大学出版社")
    # 练习：查询某书的出版社名称
    publishName =Book.objects.filter(name="python").values_list("publish__name")[0]
    publishName=Publish.objects.filter(book__name="python").values_list("name")[0]
    return render(request,"index.html",locals())

def addAuthorForBook(request):
    # -------------------多对多开始------------------------
    # 给书籍添加作者2  3  ---添加一个集合
    book_obj = Book.objects.get(id=7)  # 先获取到某本书
    author_obj = Author.objects.filter(id__in=(2,3))  # 获取作者 2 3
    book_obj.authors.add(*author_obj)  # 给书添加作者----添加一个集合

    # 给书籍添加作者4   ---添加一个实体
    book_obj.authors.add(Author.objects.get(id=4))
    return HttpResponse("为书籍添加作者成功！")
def updateAuthorForBook(request):
    # -------------------多对多开始------------------------
    # 直接在author表中修改名字
    b=Book.objects.get(id=7).authors.all()[0]
    b.name="李师师"
    b.save()
    return HttpResponse("为书籍修改作者成功！")
def deleteAuthorForBook(request):
    # -------------------多对多开始------------------------
    # 移除作者3
    book_obj = Book.objects.get(id=7)  # 先获取到某本书
    book_obj.authors.remove(3)  # 可以进行简写
   #可移除多个
    author_obj = Author.objects.filter(id=2)
    book_obj.authors.remove(*author_obj)
    return HttpResponse("为书籍删除作者成功！")
def queryAuthorForBook(request):
    # -------------------多对多开始------------------------
    #查询张三出过的书
    bookList = Book.objects.filter(authors__name="张三")
    #查询书本的平均价格
    booksAvgPrice=Book.objects.all().aggregate(Avg("price"))
    # 查询"张三"书的总价格
    booksSumPrice = Book.objects.filter(authors__name="张三").aggregate(总价格=Sum("price"))
    # 求每个人出书的平均价格
    booksAvgPriceForPeople=Book.objects.values("authors__name").annotate(price=Avg("price"))
    # 求各个出版社的最低的价格
    booksPublishMinPrice=Book.objects.values("publish__name").annotate(minprice=Min("price"))
    return render(request,"index.html",locals())

def updatePriceForBook(request):
    Book.objects.all().update(price=F("price")+10)
    return HttpResponse("为书籍添加价格成功！")

def queryPriceForBook(request):
    # -------------------多对多开始------------------------
    #查询张三出过的书，并且价格等于90(Q查询和普通查询一起使用的时候，Q放前面)
    bookList2 = Book.objects.filter(Q(price=90),authors__name="张三")
    # 查询张三出过的书，或者价格等于90
    bookList2 = Book.objects.filter(Q(price=90)|Q(authors__name="张三")).values("id","name","authors__name","price")
    # 查询不是张三出过的书
    bookList2 = Book.objects.filter(~Q(authors__name="张三"))
    #-------------------注意：bookList2为QuerySet类型，懒加载，不使用不会请求数据库---------------
    # -------------------为了减少内存中的缓存可使用--------------------------
    if bookList2.exists():
        print("不想向内存中添加数据，仅仅是判断是否存在")
    #-------------------迭代器--------------------------
    bookList2=bookList2.iterator()
    for ite in bookList2:
        print("转换成迭代器以后，用一次就没有了")
    return render(request,"index.html",locals())

Views

"""Django_ORM2 URL Configuration

The `urlpatterns` list routes URLs to views. For more information please see:
    https://docs.djangoproject.com/en/2.1/topics/http/urls/
Examples:
Function views
    1. Add an import:  from my_app import views
    2. Add a URL to urlpatterns:  path('', views.home, name='home')
Class-based views
    1. Add an import:  from other_app.views import Home
    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
Including another URLconf
    1. Import the include() function: from django.urls import include, path
    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
"""
from django.contrib import admin
from django.urls import path
from APP2 import views
urlpatterns = [
    path('admin/', admin.site.urls),
    path('index/', views.index,name="index"), #创建首页
    path('addbook/', views.addbook,name="addbook"), #新增书籍
    path('updatebook/', views.updatebook, name="updatebook"),  # 新增书籍
    path('deltebook/', views.deltebook, name="deltebook"),  # 新增书籍
    path('querybook/', views.querybook, name="querybook"),  # 新增书籍
    path('addAuthorForBook/', views.addAuthorForBook, name="addAuthorForBook"),  # 给书籍添加作者
    path('updateAuthorForBook/', views.updateAuthorForBook, name="updateAuthorForBook"),  # 修改书籍的作者
    path('deleteAuthorForBook/', views.deleteAuthorForBook, name="deleteAuthorForBook"),  # 删除书籍的作者
    path('queryAuthorForBook/', views.queryAuthorForBook, name="queryAuthorForBook"),  # 查询书籍的作者
    path('updatePriceForBook/', views.updatePriceForBook, name="updatePriceForBook"),  # 给书籍添加10元
    path('queryPriceForBook/', views.queryPriceForBook, name="queryPriceForBook"),  # Q查询

]

urls

"""
Django settings for Django_ORM2 project.

Generated by 'django-admin startproject' using Django 2.1.4.

For more information on this file, see
https://docs.djangoproject.com/en/2.1/topics/settings/

For the full list of settings and their values, see
https://docs.djangoproject.com/en/2.1/ref/settings/
"""

import os

# Build paths inside the project like this: os.path.join(BASE_DIR, ...)
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))

# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/2.1/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = '5%@&gx+jf88o2(xud0@7nditgvoch%p6#+8e)dx$s7g6n5jdj^'

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True

ALLOWED_HOSTS = []

# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'APP2.apps.App2Config',
]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'Django_ORM2.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [os.path.join(BASE_DIR, 'templates')]
        ,
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

WSGI_APPLICATION = 'Django_ORM2.wsgi.application'

# Database
# https://docs.djangoproject.com/en/2.1/ref/settings/#databases

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'Django_ORM',  # 你的数据库名称
        'USER': 'root',  # 你的数据库用户名
        'PASSWORD': '12qwaszx!@QWASZX',  # 你的数据库密码
        'HOST': '',  # 你的数据库主机，留空默认为localhost
        'PORT': '',  # 你的数据库端口

    }
}

# Password validation
# https://docs.djangoproject.com/en/2.1/ref/settings/#auth-password-validators

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]

# Internationalization
# https://docs.djangoproject.com/en/2.1/topics/i18n/

LANGUAGE_CODE = 'en-us'

TIME_ZONE = 'UTC'

USE_I18N = True

USE_L10N = True

USE_TZ = True

# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/2.1/howto/static-files/

STATIC_URL = '/static/'
LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'handlers': {
        'console':{
            'level':'DEBUG',
            'class':'logging.StreamHandler',
        },
    },
    'loggers': {
        'django.db.backends': {
            'handlers': ['console'],
            'propagate': True,
            'level':'DEBUG',
        },
    }
}

settings

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        *{
           margin: 0px;
           padding: 0px;
        }
        .head{
            line-height: 40px;
            background-color: green;
            color: white;
            text-align: center;
        }
    </style>
</head>
<body>
    <div class="outer">
        <div class="head">标题</div>
        <div class="content">
            <a href="/addbook/">添加书籍</a>
            <a href="/updatebook/">修改书籍</a>
            <a href="/deltebook/">删除书籍</a>
            <a href="/querybook/">查询书籍</a>
            <br/>
            <a href="/addAuthorForBook/">给书籍添加作者</a>
            <a href="/updateAuthorForBook/">修改书籍的作者</a>
            <a href="/deleteAuthorForBook/">删除书籍的作者</a>
            <a href="/queryAuthorForBook/">查询书籍的作者</a>
            <br/>
            <a href="/updatePriceForBook/">给书籍添加10元（F查询）</a>
            <a href="/queryPriceForBook/">查询书籍（Q查询）</a>
        </div>
        <div>
            {% if bookList.count > 0 %}
                <table>
                    <tr><td>序号</td><td>书名</td><td>作者</td><td>价格</td></tr>
                    {% for book in bookList %}
                        <tr><td>{{ book.id }}</td><td>{{ book.name }}</td><td>暂无</td><td>{{ book.price }}</td></tr>
                    {% endfor %}

                </table>
            {% endif %}
            查询出一本书所在的出版社：{{ publishName }}
            <br/>
            返回数字：{{ num }}
            <br/>
            多对多查询
            <br/>
            书的平均价格：{{ booksAvgPrice }}
            <br/>
            书的总价格：{{ booksSumPrice }}
            <br/>
            {% if booksAvgPriceForPeople.count > 0 %}
                <table>
                    <tr><td>作者</td><td>价格</td></tr>
                    {% for authorPrice in booksAvgPriceForPeople %}
                        <tr> <td>{{ authorPrice.authors__name }}</td><td>{{ authorPrice.price }}</td></tr>
                    {% endfor %}

                </table>
            {% endif %}
         <br/>
            {% if booksPublishMinPrice.count > 0 %}
                <table>
                    <tr><td>出版社</td><td>最低价格</td></tr>
                    {% for publishPrice in booksPublishMinPrice %}
                        <tr> <td>{{ publishPrice.publish__name}}</td><td>{{ publishPrice.minprice }}</td></tr>
                    {% endfor %}

                </table>
            {% endif %}
        <br/>
         {% if bookList2.count > 0 %}
                <table>
                    <tr><td>序号</td><td>书名</td><td>作者</td><td>价格</td></tr>
                    {% for book in bookList2 %}
                        <tr><td>{{ book.id }}</td><td>{{ book.name }}</td><td>{{ book.authors__name }}</td><td>{{ book.price }}</td></tr>
                    {% endfor %}

                </table>
            {% endif %}
        </div>
    </div>
</body>
</html>

index.html

六、 总结

---

一、必知必会13条

1：返回具体对象

　　 get() first() last()

2：返回QuerySet

　　all() , filter() , exclude() , order_by() , reverse() , distinct()

3：返回指定字段的QuerySet

　　values() values_list()

4：返回数字

　　count()

5：返回布尔值

　　exists()

二、单表中双下划线

　　__gt 　　　　   # greater than 大于
　　__lt 　　　　     # less than 小于
　　__gte 　　　　  # greater than equal 大于等于
　　__lte 　　　　　#小于等于
　　_in 　　　　 　　# in
　　__range　　　　# 什么范围
　　__contains 　　  # like 包含
　　__startswith 　　# 以什么开头
　　__endswith 　　 # 以什么结束
　　__isnull=True 　 # 是否为空
　　__year 　　　　 # 年
　　__month 　　     # 月

三、高级操作

　　aggregate　　#聚合

　　annotate　　  #分组

　　F 和 Q

　　事务