Python学习---抽屉框架分析[ORM操作]180314

Django ORM操作

    1. 字段操作
         class User(model.Model);
             u=字段
        用处：
            1 .admin中的字段验证
            2. obj.clean_fields() 进行自定义的验证
            3. 利用Djanfo Form进行验证，此时前台和后台的操作分开
               但form和model里的字段重复【推荐使用】
                    ModelForm组件验证
                      name
                      email
                   model组件操作数据
                       name
                       email
            4. 利用ModelForm实现models的字段验证【Admin就是基于此验证的】
               2个文件直接的依赖性太强，适合小项目【不推荐使用】
                   ModelForm组件验证
                      直接采用model里面的字段
                   model组件操作数据
                       name
                       email
    2. 内容操作

案例操作

字段用处1. admin中的字段验证，仅仅用于单表

settings.py

INSTALLED_APPS = [
   ...
 'app01',   # 注册app
]
STATICFILES_DIRS = (os.path.join(BASE_DIR, "statics"),)  # 现添加的配置,这里是元组，注意逗号
TEMPLATES = [
   ...
   'DIRS': [os.path.join(BASE_DIR, 'templates')],
]

admin.py

from django.contrib import admin
from app01 import models
# Register your models here.

# 添加信息到Django Admin
admin.site.register(models.Test)

urls.py

from django.contrib import admin
from django.urls import path
from django.conf.urls import url, include
from app01 import views
urlpatterns = [
   url('admin/', admin.site.urls),
]

views.py

from django.shortcuts import render, redirect
from app01 import models

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初始化数据库

python manage.py makemigrations
python manage.py migrate

创建admin用户

python manage.py createsuperuser

字段用处2. obj.clean_fields() 进行自定义的验证

settings.py

INSTALLED_APPS = [
   ...
 'app01',   # 注册app
]
STATICFILES_DIRS = (os.path.join(BASE_DIR, "statics"),)  # 现添加的配置,这里是元组，注意逗号
TEMPLATES = [
   ...
   'DIRS': [os.path.join(BASE_DIR, 'templates')],
]

urls.py

from django.contrib import admin
from django.urls import path
from django.conf.urls import url, include
from app01 import views
urlpatterns = [
   # 测试
 url(r'^test.html', views.test),
]

models.py

from django.db import models
class Test(models.Model):
    username = models.CharField(max_length=32, unique=True)
    email = models.EmailField()

models.py

from django.db import models
class Test(models.Model):
    username = models.CharField(max_length=32, unique=True)
    email = models.EmailField()

views.py

from django.shortcuts import render, redirect
from app01 import models
# 测试
def test(request):
    # 实例化一个对象
    obj = models.Test(username='root', email='hhhlive.com')
    # model进行参数的校验
    obj.clean_fields()
    obj.save()  # 数据进行保存
    return HttpResponse("test")

页面显示；

用处4： 基于ModelForm实现Django Admin字段添加[不更改数据库]

settings.py

INSTALLED_APPS = [
   ...
 'app01',   # 注册app
]
STATICFILES_DIRS = (os.path.join(BASE_DIR, "statics"),)  # 现添加的配置,这里是元组，注意逗号
TEMPLATES = [
   ...
   'DIRS': [os.path.join(BASE_DIR, 'templates')],
]

urls.py

from django.contrib import admin
from django.urls import path
from django.conf.urls import url, include
from app01 import views
urlpatterns = [
   url('admin/', admin.site.urls),
]

model.py

from django.db import models
class Test(models.Model):
    username = models.CharField(max_length=32, unique=True)
    email = models.EmailField()

admin.py

from app01 import models
from  django import forms
from django.contrib import admin
class TestForm(forms.ModelForm):  # ModelForm和Form一样均继承了Model
    username = forms.CharField(error_messages={'required':'用户名不能为空'})
    email = forms.EmailField(error_messages={'invalid': '邮箱格式错误'})
    age = forms.IntegerField(error_messages={"required": '请输入数字'})
    class Meta:
        models = models.Test
        # fields = ('username',)
        fields = '__all__'    # 将model里面Test的全部字段倒给TestForm,此时具有验证功能
# 添加信息到Django Admin
# 此时Django Admin 里面有5个字段， Test的2个 + TestForm的3个
admin.site.register(models.Test, TestForm)