day13-3django后端开发

一、配置

1.修改文件目录后，需要修改的位置

2.修改运行目录

3.复制db路径，重新连接数据库

 2.删除数据的操作步骤

https://blog.csdn.net/doulihang/article/details/102973565

3.数据库多对多的生成方式

django里面的多对多关系，它是通过建立第三张表来存储对应的关系。

在models模块

class Teacher(models.Model):
    name = models.CharField(max_length=50)

    def __str__(self):
        return self.name

    class Meta:
        db_table = 'teacher'

class Student(models.Model):
    name = models.CharField(max_length=50,verbose_name='学生姓名')
    teacher = models.ManyToManyField(Teacher,verbose_name='老师')

    def __str__(self):
        return self.name

    class Meta:
        db_table = 'student'

2.添加到admin中后，通过页面创建数据。查看数据库中的显示

#新增数据，新增多对多关系
#正向查询(在models里面有多对多的查询)
stu = models.Student.objects.create(name="fangdan")
stu.teacher.add(1)
stu.teacher.add(2)

# get_or_create如果存在就get，如果不存在就创建
stu,status = models.Student.objects.get_or_create(name="李想")
print(stu)
stu.teacher.remove(1)#从关系里面删除一个老师
print(stu.teacher.all())#查看所有老师
print(stu.teacher.get(id=2))


#反向查询，model里面没有多对多的这个字段
teacher,status = models.Teacher.objects.get_or_create(name= '大老师')
print(teacher.student_set.all())
# print(teacher.student_set.remove())
# print(teacher.student_set.add())
print(teacher.student_set.filter())
print(teacher.student_set.count())
# print(teacher.student_set.clear())
# print(teacher.student_set.create())

4.自关联

class Case(models.Model):
    name = models.CharField(max_length=50)
    url = models.CharField(max_length=10)
    method = models.CharField(max_length=20)
    param = models.CharField(max_length=30)
    #自关联,null=True数据不能为空，blank=True admin中不能为空
    require_case = models.ForeignKey('self',on_delete=models.PROTECT,verbose_name='依赖用例',null=True,blank=True)

    def __str__(self):
        return self.name

    class Meta:
        db_table = 'case'
        ordering = ['-id']

 5.一对一的关系

class Account(models.Model):
    balance = models.IntegerField(verbose_name='余额',default=0)

    class Meta:
        db_table = 'account'

class User(models.Model):
    name = models.CharField(max_length=50)
    account = models.OneToOneField(Account,on_delete=models.CASCADE,verbose_name='账户')#级联

    def __str__(self):
        return self.name

    class Meta:
        db_table = 'user'

 6.数据库路由：不同的app访问不同的数据库

user访问sqllite，order访问的是mysql数据库

数据库配置：sqllite是文件数据库

pip install django_redis==4.10

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
    },
    'mysql':{
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'jxz',
        'HOST': '118.24.3.40',
        'PASSWORD': '123456',
        'USER': 'jxz',
        'PORT': 3306,
    }
}#数据库配置

CACHES = {
    "default": {
        "BACKEND": "django_redis.cache.RedisCache",
        "LOCATION": "redis://118.24.3.40:6379/0",
        "OPTIONS": {
            "CLIENT_CLASS": "django_redis.client.DefaultClient",
            "CONNECTION_POOL_KWARGS": {"max_connections": 100},
            "PASSWORD": "HK139bc&*",  # 密码
        }
    },
    "redis2": {
        "BACKEND": "django_redis.cache.RedisCache",
        "LOCATION": "redis://118.24.3.40:6379/1",
        "OPTIONS": {
            "CLIENT_CLASS": "django_redis.client.DefaultClient",
            "CONNECTION_POOL_KWARGS": {"max_connections": 100, 'decode_responses': True},
            "PASSWORD": "HK139bc&*",  # 密码
        }
    }
}  # redis配置

DATABASE_ROUTERS = ['sky.database_router.DatabaseAppsRouter'] #与下面的类的路径

写一个数据库路由的类

db_mapper = {
    'sqlite':'default',
    'order':'mysql'

}

class DatabaseAppsRouter(object):
    def db_for_read(self, model, **hints):
        print('走了读',model)
        app_label = model._meta.app_label
        if app_label in db_mapper:
            return db_mapper[app_label]
        return 'default'

    def db_for_write(self, model, **hints):
        print('走了写',model)
        app_label = model._meta.app_label
        if app_label in db_mapper:
            return db_mapper[app_label]
        return 'default'

运行后django会报错，解决方法，是在sky的下面创建一个__init__.py,再启动就不会报错了

import pymysql
pymysql.install_as_MySQLdb()

在order中的models中写入

from django.db import models

# Create your models here.
class FDD(models.Model):
    name = models.CharField(max_length=50)

    def __str__(self):
        return self.name

    class Meta:
        db_table = 'Fdd'
        # app_label = 'new_user'因为是在order应用中写的，所以不用写这个


#makemigrations order
#migrate
# migrate order --database mysql

7.fvb,cvb(function(def) view,class view)

===参照user中的views 和order中的views的区别

8.urls拆分

order和user中的有views，在sky的urls中如果添加

方法一：使用别名as

from user import views
# from order import views as o_view

urlpatterns = [
    path('admin/', admin.site.urls),
    path('',include('user.urls')),
    # path('user', o_view.UserView.as_view()),

]

方法二：拆分

分别在order和user中创建urls.py文件

from . import views

from django.urls import path

urlpatterns = [
    path('user',views.UserView.as_view(),),
]

from . import views

from django.urls import path
from .import views,new_views

urlpatterns = [
    path('index', views.index),
    # path('', views.get_sign),
    # path('category', views.category_view),
    path('category/<int:id>', views.category),
    path('detail/<int:id>', views.article),
    path('test', views.test),
    path('', views.index),
    path('add', views.add_article),
    path('interface', new_views.InterfaceView.as_view()),

]

from django.contrib import admin
from django.urls import path,include
from user import views
# from order import views as o_view

urlpatterns = [
    path('admin/', admin.site.urls),
    path('',include('user.urls')),
    path('order/',include('order.urls')),

]

9.中间件：类似上下文管理器