Django进阶

1.orm

1.1 基本操作

orm，关系对象映射。

类      --> SQL -->     表
对象    --> SQL -->     数据

特点：开发效率高、执行效率低（ 程序写的垃圾SQL ）。

编写ORM操作的步骤：

• settings.py，连接数据库

  DATABASES = {'default': {'ENGINE': 'django.db.backends.sqlite3','NAME': BASE_DIR / 'db.sqlite3',}
  }
  

• settings.py，注册app

  INSTALLED_APP = [..."app01.apps.App01Config"
  ]
  

• 编写models.类

  class UserInfo(models.Model):.........
  

• 执行命令

  python manage.py makemigrations    # 找到所有已注册的app中的models.py中的类读取 -> migrations配置
  python manage.py migrate           # 读取已注册的app下的migrations配置 -> SQL语句  -> 同步数据库
  

1.2 连接数据库

DATABASES = {'default': {'ENGINE': 'django.db.backends.sqlite3','NAME': BASE_DIR / 'db.sqlite3',}
}

DATABASES = {'default': {'ENGINE': 'django.db.backends.mysql','NAME': 'xxxxxxxx',  # 数据库名字'USER': 'root','PASSWORD': 'root123','HOST': '127.0.0.1',  # ip'PORT': 3306,}
}

项目连接MySQL：

• 安装MySQL & 启动MySQL服务

• 手动创建数据库

• django的settings.py配置

  DATABASES = {'default': {'ENGINE': 'django.db.backends.mysql','NAME': 'xxxxxxxx',  # 数据库名字'USER': 'root','PASSWORD': 'root123','HOST': '127.0.0.1',  # ip'PORT': 3306,}
  }
  

• 安装第三方组件

  • pymysql

    pip install pymysql
    

    项目根目录/项目名目录/__init__.pyimport pymysqlpymysql.install_as_MySQLdb()
    

  • mysqlclient

    pip install mysqlclient
    

    电脑上先提前安装MySQL。
    

其他数据库：

DATABASES = {'default': {'ENGINE': 'django.db.backends.postgresql','NAME': 'mydatabase','USER': 'mydatabaseuser','PASSWORD': 'mypassword','HOST': '127.0.0.1','PORT': 5432,}
}# 需要 pip install psycopg2

DATABASES = {'default': {'ENGINE': 'django.db.backends.oracle','NAME': "xxxx",  # 库名"USER": "xxxxx",  # 用户名"PASSWORD": "xxxxx",  # 密码"HOST": "127.0.0.1",  # ip"PORT": 1521,  # 端口}
}
# 需要 pip install cx-Oracle

1.3 连接池

django默认内置没有数据库连接池 。

pymysql   -> 操作数据库
DBUtils   -> 连接池

https://pypi.org/project/django-db-connection-pool/

pip install django-db-connection-pool

DATABASES = {"default": {'ENGINE': 'dj_db_conn_pool.backends.mysql','NAME': 'day04',  # 数据库名字'USER': 'root','PASSWORD': 'root123','HOST': '127.0.0.1',  # ip'PORT': 3306,'POOL_OPTIONS': {'POOL_SIZE': 10,  # 最小'MAX_OVERFLOW': 10,  # 在最小的基础上，还可以增加10个，即：最大20个。'RECYCLE': 24 * 60 * 60,  # 连接可以被重复用多久，超过会重新创建，-1表示永久。'TIMEOUT':30, # 池中没有连接最多等待的时间。}}
}

注意：组件django-db-connection-pool不是特别厉害。拿了另外一个支持SQLAchemy数据库连接池的组件。

1.4 多数据库

django支持项目连接多个数据库。

DATABASES = {"default": {'ENGINE': 'dj_db_conn_pool.backends.mysql','NAME': 'day05db',  # 数据库名字'USER': 'root','PASSWORD': 'root123','HOST': '127.0.0.1',  # ip'PORT': 3306,'POOL_OPTIONS': {'POOL_SIZE': 10,  # 最小'MAX_OVERFLOW': 10,  # 在最小的基础上，还可以增加10个，即：最大20个。'RECYCLE': 24 * 60 * 60,  # 连接可以被重复用多久，超过会重新创建，-1表示永久。'TIMEOUT': 30,  # 池中没有连接最多等待的时间。}},"bak": {'ENGINE': 'dj_db_conn_pool.backends.mysql','NAME': 'day05bak',  # 数据库名字'USER': 'root','PASSWORD': 'root123','HOST': '127.0.0.1',  # ip'PORT': 3306,'POOL_OPTIONS': {'POOL_SIZE': 10,  # 最小'MAX_OVERFLOW': 10,  # 在最小的基础上，还可以增加10个，即：最大20个。'RECYCLE': 24 * 60 * 60,  # 连接可以被重复用多久，超过会重新创建，-1表示永久。'TIMEOUT': 30,  # 池中没有连接最多等待的时间。}},
}

1.4.1 读写分离

192.168.1.2       default master   [写]组件
192.168.2.12      bak slave    [读]

• 生成数据库表

  python manage.py makemigrations    # 找到所有已注册的app中的models.py中的类读取 -> migrations配置python manage.py migrate
  python manage.py migrate --database=default
  python manage.py migrate --database=bak
  

• 后续再进行开发时

  models.UserInfo.objects.using("default").create(title="武沛齐")models.UserInfo.objects.using("bak").all()
  

• 编写router类，简化【后续再进行开发时】

  class DemoRouter(object):def db_for_read(...):return "bak"def db_for_write(...):return "default"
  

  router = ["DemoRouter"]
  

  

1.4.2 分库（多个app ->多数据库）

100张表，50表-A数据库【app02】；50表-B数据库【app02】。

• app01/models

  from django.db import modelsclass UserInfo(models.Model):title = models.CharField(verbose_name="标题", max_length=32)

• app02/models

  from django.db import modelsclass Role(models.Model):title = models.CharField(verbose_name="标题", max_length=32)
  

• 命令

  python manage.py makemigrations
  

  python manage.py migrate app01 --database=default
  

  python manage.py migrate app02 --database=bak
  

  

• 读写操作

  from django.shortcuts import render, HttpResponsefrom app01 import models as m1
  from app02 import models as m2def index(request):# app01中的操作 -> defaultv1 = m1.UserInfo.objects.all()print(v1)# app02中的操作 -> bakv2 = m2.Role.objects.using('bak').all()print(v2)return HttpResponse("返回")
  

• router

  

1.4.3 分库（单app）

100张表，50表-A数据库；50表-B数据库。

from django.shortcuts import render, HttpResponsefrom app01 import models as m1def index(request):# app01中的操作 -> defaultv1 = m1.UserInfo.objects.all()print(v1)# app01中的操作 -> bakv2 = m1.Role.objects.using('bak').all()print(v2)return HttpResponse("返回")

1.4.4 注意事项

• 分库，表拆分到不用数据库。

  一定不要跨数据库做关联  -> django不支持怎么办？
  尽可能的将有关联的表放在一个库中。
  

  

• 为什么表拆分到不同的库？

1.5 表关系

• 单表

  class Role(models.Model):title = models.CharField(verbose_name="标题", max_length=32)
  

• 一对多

  

• 多对多
  

  如果关系表中只有3列。

  class Boy(models.Model):"""1   杰森斯坦森2   汤普森"""name = models.CharField(verbose_name="标题", max_length=32, unique=True)b = models.ManyToManyField(to="Girl")class Girl(models.Model):"""1   alex2   苑昊"""name = models.CharField(verbose_name="标题", max_length=32, unique=True)
  

  class Boy(models.Model):"""1   杰森斯坦森2   汤普森"""name = models.CharField(verbose_name="标题", max_length=32, unique=True)class Girl(models.Model):"""1   alex2   苑昊"""name = models.CharField(verbose_name="标题", max_length=32, unique=True)b = models.ManyToManyField(to="Boy")
  

  class Boy(models.Model):name = models.CharField(verbose_name="标题", max_length=32, unique=True)class Girl(models.Model):name = models.CharField(verbose_name="标题", max_length=32, unique=True)class B2G(models.Model):bid = models.ForeignKey(to="Boy", on_delete=models.CASCADE)gid = models.ForeignKey(to="Girl", on_delete=models.CASCADE)address = models.CharField(verbose_name="地点", max_length=32)
  

• 一对一

  表，100列     ->  50A表      50B表博客园为例：- 注册，用户名、密码，无法创建博客- 开通博客  地址/
  

  

1.6 数据操作

• 单表

  class Role(models.Model):title = models.CharField(verbose_name="标题", max_length=32)
  

  # obj1 = models.Role.objects.create(title="管理员", od=1)
  # obj2 = models.Role.objects.create(**{"title": "管理员", "od": 1})# 内存 -> save
  # obj = models.Role(title="客户", od=1)
  # obj.od = 100
  # obj.save()# obj = models.Role(**{"title": "管理员", "od": 1})
  # obj.od = 100
  # obj.save()
  

  

  # models.Role.objects.all().delete()
  models.Role.objects.filter(title="管理员").delete()
  

  models.Role.objects.all().update(od=99)
  models.Role.objects.filter(id=7).update(od=99, title="管理员")
  models.Role.objects.filter(id=7).update(**{"od": 99, "title": "管理员"})
  

  # QuerySet = [obj, obj]
  v1 = models.Role.objects.all()
  for obj in v1:print(obj, obj.id, obj.title, obj.od)# QuerySet = []
  # v2 = models.Role.objects.filter(od=99, id=99)
  v2 = models.Role.objects.filter(**{"od": 99, "id": 99})
  for obj in v2:print(obj, obj.id, obj.title, obj.od)v3 = models.Role.objects.filter(id=99)
  print(v3.query)v3 = models.Role.objects.filter(id__gt=2)
  print(v3.query)v3 = models.Role.objects.filter(id__gte=2)
  print(v3.query)v3 = models.Role.objects.filter(id__lt=2)
  print(v3.query)v3 = models.Role.objects.filter(id__in=[11, 22, 33])
  print(v3.query)v3 = models.Role.objects.filter(title__contains="户")
  print(v3.query)v3 = models.Role.objects.filter(title__startswith="户")
  print(v3.query)v3 = models.Role.objects.filter(title__isnull=True)
  print(v3.query)
  

  v3 = models.Role.objects.filter(id=99)
  print(v3.query)
  # 不等于
  v3 = models.Role.objects.exclude(id=99).filter(od=88)
  print(v3.query)
  

  # queryset=[obj,obj]
  v3 = models.Role.objects.filter(id=99)# queryset=[{'id': 6, 'title': '客户'}, {'id': 7, 'title': '客户'}]
  v4 = models.Role.objects.filter(id__gt=0).values("id", 'title')# QuerySet = [(6, '客户'), (7, '客户')]
  v5 = models.Role.objects.filter(id__gt=0).values_list("id", 'title')
  print(v5[0])
  

  v6 = models.Role.objects.filter(id__gt=0).first()
  # print(v6)  # 对象v7 = models.Role.objects.filter(id__gt=10).exists()
  print(v7)  # True/False
  

  # asc
  v8 = models.Role.objects.filter(id__gt=0).order_by("id")# id desc  od asc
  v9 = models.Role.objects.filter(id__gt=0).order_by("-id", 'od')
  

• 一对多

  class Depart(models.Model):""" 部门 """title = models.CharField(verbose_name="标题", max_length=32)class Admin(models.Model):name = models.CharField(verbose_name="姓名", max_length=32)pwd = models.CharField(verbose_name="密码", max_length=32)depart = models.ForeignKey(verbose_name="部门", to="Depart", on_delete=models.CASCADE)
  

  models.Admin.objects.create(name='武沛齐1', pwd='123123123', depart_id=2)
  # models.Admin.objects.create(**{..})obj = models.Depart.objects.filter(id=2).first()
  models.Admin.objects.create(name='武沛齐2', pwd='123123123', depart=obj)
  models.Admin.objects.create(name='武沛齐2', pwd='123123123', depart_id=obj.id)
  

  # filter()   # 当前表的字段 + depart__字段    -> 连表和条件# 找到部门id=3的所有的员工，删除
  # models.Admin.objects.filter(depart_id=3).delete()# 删除销售部的所有员工
  # obj = models.Depart.objects.filter(title="销售部").first()
  # models.Admin.objects.filter(depart_id=obj.id).delete()# models.Admin.objects.filter(depart__title="销售部", name='武沛齐').delete()
  

  # 1. select * from admin    					queryset=[obj,obj,]
  v1 = models.Admin.objects.filter(id__gt=0)
  for obj in v1:print(obj.name, obj.pwd, obj.id, obj.depart_id)# 2. select * from admin inner join depart      queryset=[obj,obj,]
  v2 = models.Admin.objects.filter(id__gt=0).select_related("depart")
  for obj in v2:print(obj.name, obj.pwd, obj.id, obj.depart_id, obj.depart.title)# 3. select id,name.. from admin inner join depart      queryset=[{},{}]
  v3 = models.Admin.objects.filter(id__gt=0).values("id", 'name', 'pwd', "depart__title")
  print(v3)# 4. select id,name.. from admin inner join depart      queryset=[(),()]
  v4 = models.Admin.objects.filter(id__gt=0).values_list("id", 'name', 'pwd', "depart__title")
  print(v4)
  

  # 查询
  # models.Admin.objects.filter(id=2).update(name='xxx', pwd='xxxx')
  # models.Admin.objects.filter(name="武沛齐").update(depart_id=2)# models.Admin.objects.filter(id=2).update(depart__title="技术部")  -> 只能更新自己表字段
  

  

• 多对多

  

  from django.db import modelsclass Boy(models.Model):name = models.CharField(verbose_name="姓名", max_length=32, db_index=True)class Girl(models.Model):name = models.CharField(verbose_name="姓名", max_length=32, db_index=True)class B2G(models.Model):bid = models.ForeignKey(to="Boy", on_delete=models.CASCADE)gid = models.ForeignKey(to="Girl", on_delete=models.CASCADE)address = models.CharField(verbose_name="地点", max_length=32)
  

  def index(request):# models.Boy.objects.create(name="宝强")# models.Boy.objects.create(name="羽凡")# models.Boy.objects.create(name="乃亮")## models.Girl.objects.bulk_create(#     objs=[models.Girl(name="小路"), models.Girl(name="百合"), models.Girl(name="马蓉")],#     batch_size=3# )# 创建关系# models.B2G.objects.create(bid_id=1, gid_id=3, address="北京")# models.B2G.objects.create(bid_id=1, gid_id=2, address="北京")# models.B2G.objects.create(bid_id=2, gid_id=2, address="北京")# models.B2G.objects.create(bid_id=2, gid_id=1, address="北京")# b_obj = models.Boy.objects.filter(name='宝强').first()# g_object = models.Girl.objects.filter(name="小路").first()# models.B2G.objects.create(bid=b_obj, gid=g_object, address="北京")# 1.宝强都与谁约会。# queyset=[obj,obj,obj]# q = models.B2G.objects.filter(bid__name='宝强').select_related("gid")# for item in q:#     print(item.id, item.address, item.bid.name, item.gid.name)# q = models.B2G.objects.filter(bid__name='宝强').values("id", 'bid__name', 'gid__name')# for item in q:#     print(item['id'], item['bid__name'], item['gid__name'])# 2.百合 都与谁约会。# q = models.B2G.objects.filter(gid__name='百合').values("id", 'bid__name', 'gid__name')# for item in q:#     print(item['id'], item['bid__name'], item['gid__name'])# 3.删除# models.B2G.objects.filter(id=1).delete()# models.Boy.objects.filter(id=1).delete()return HttpResponse("返回")
  

• 一对一
  

2.cookie和session

2.1 cookie

127.0.0.1       v1.wupeiqi.com
127.0.0.1       v2.wupeiqi.com

2.2 配置session

• 文件版

  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',
  ]# session
  SESSION_ENGINE = 'django.contrib.sessions.backends.file'
  SESSION_FILE_PATH = 'xxxx' SESSION_COOKIE_NAME = "sid"  # Session的cookie保存在浏览器上时的key，即：sessionid＝随机字符串
  SESSION_COOKIE_PATH = "/"  # Session的cookie保存的路径
  SESSION_COOKIE_DOMAIN = None  # Session的cookie保存的域名
  SESSION_COOKIE_SECURE = False  # 是否Https传输cookie
  SESSION_COOKIE_HTTPONLY = True  # 是否Session的cookie只支持http传输
  SESSION_COOKIE_AGE = 1209600  # Session的cookie失效日期（2周）SESSION_EXPIRE_AT_BROWSER_CLOSE = False  # 是否关闭浏览器使得Session过期
  SESSION_SAVE_EVERY_REQUEST = True  # 是否每次请求都保存Session，默认修改之后才保存
  

• 数据库

  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',
  ]# session
  SESSION_ENGINE = 'django.contrib.sessions.backends.db'SESSION_COOKIE_NAME = "sid"  # Session的cookie保存在浏览器上时的key，即：sessionid＝随机字符串
  SESSION_COOKIE_PATH = "/"  # Session的cookie保存的路径
  SESSION_COOKIE_DOMAIN = None  # Session的cookie保存的域名
  SESSION_COOKIE_SECURE = False  # 是否Https传输cookie
  SESSION_COOKIE_HTTPONLY = True  # 是否Session的cookie只支持http传输
  SESSION_COOKIE_AGE = 1209600  # Session的cookie失效日期（2周）SESSION_EXPIRE_AT_BROWSER_CLOSE = False  # 是否关闭浏览器使得Session过期
  SESSION_SAVE_EVERY_REQUEST = True  # 是否每次请求都保存Session，默认修改之后才保存
  

• 缓存

  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',
  ]# session
  SESSION_ENGINE = 'django.contrib.sessions.backends.cache'
  SESSION_CACHE_ALIAS = 'default' SESSION_COOKIE_NAME = "sid"  # Session的cookie保存在浏览器上时的key，即：sessionid＝随机字符串
  SESSION_COOKIE_PATH = "/"  # Session的cookie保存的路径
  SESSION_COOKIE_DOMAIN = None  # Session的cookie保存的域名
  SESSION_COOKIE_SECURE = False  # 是否Https传输cookie
  SESSION_COOKIE_HTTPONLY = True  # 是否Session的cookie只支持http传输
  SESSION_COOKIE_AGE = 1209600  # Session的cookie失效日期（2周）SESSION_EXPIRE_AT_BROWSER_CLOSE = False  # 是否关闭浏览器使得Session过期
  SESSION_SAVE_EVERY_REQUEST = True  # 是否每次请求都保存Session，默认修改之后才保存
  

3.缓存

• 服务器 + redis安装启动

• django

  • 安装连接redis包

    pip install django-redis
    

  • settings.py

    CACHES = {"default": {"BACKEND": "django_redis.cache.RedisCache","LOCATION": "redis://127.0.0.1:6379","OPTIONS": {"CLIENT_CLASS": "django_redis.client.DefaultClient","CONNECTION_POOL_KWARGS": {"max_connections": 100}# "PASSWORD": "密码",}}
    }
    

  • 手动操作redis

    from django_redis import get_redis_connectionconn = get_redis_connection("default")
    conn.set("xx","123123")
    conn.get("xx")