python(04) Django新增app

目的：在Django新增模块-对数据库做读取、写入操作

1. 创建 APP
   Django规定，如果要使用模型，必须要创建一个app。我们使用以下命令创建一个 TestModel 的 app:

python manage.py startapp TestModel

得到的目录结构如下：

TestProject
   |-- TestModel
   |   |-- migrations
   |   |   |-- __init__.py
   |   |-- __init__.py
   |   |-- admin.py
   |   |-- models.py
   |   |-- tests.py
   |   | -- views.py

2. 添加类

# models.py
from django.db import models
class Test(models.Model):
    name = models.CharField(max_length=20)

以上的类名代表了数据库中的表名，且继承了models.Model，类里面的字段代表数据表中的字段(name)，数据类型则由CharField（相当于varchar）、DateField（相当于datetime）， max_length 参数限定长度。
接下来在settings.py中找到INSTALLED_APPS这一项，如下：

INSTALLED_APPS = [    
    'django.contrib.admin',  
    'django.contrib.auth',   
    'django.contrib.contenttypes',   
    'django.contrib.sessions',   
    'django.contrib.messages',   
    'django.contrib.staticfiles',  
    'TestModel',
]

3. 将类生成数据库表

D:\pythonworkspace\TestProject>python manage.py makemigrations
Migrations for 'TestModel':
  TestModel\migrations\0001_initial.py:
    - Create model Test
D:\pythonworkspace\TestProject>python manage.py migrate
System check identified some issues:
WARNINGS:
?: (mysql.W002) MySQL Strict Mode is not set for database connection 'default'
        HINT: MySQL's Strict Mode fixes many data integrity problems in MySQL, s
uch as data truncation upon insertion, by escalating warnings into errors. It is
 strongly recommended you activate it. See: https://docs.djangoproject.com/en/1.
10/ref/databases/#mysql-sql-mode
Operations to perform:
  Apply all migrations: TestModel, admin, auth, contenttypes, sessions
Running migrations:
  Applying TestModel.0001_initial... OK

数据库中新增了testmodel_test表，字段名为id,name
会在migrations中生成一个0001_initial.py文件

from __future__ import unicode_literals
from django.db import migrations, modelsclass Migration(migrations.Migration):    
        initial = True    
        dependencies = [    
        ]    
        operations = [        
               migrations.CreateModel(            
                     name='Test',           
                     fields=[               
                     ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),                
                     ('name', models.CharField(max_length=20)),           
                    ],       
              ),    
      ]

4. 写入数据库
   testdb文件 写入数据

def add(request):    
   nameq = request.GET.get('q')   
   test1 = Test(name=nameq)    
   test1.save()   
   return HttpResponse("<p>add data ok</p>" + nameq)

页面

<form action="/addtest/" method="get">    
<input type="text" name="q">    
<input type="submit" value="Add">
</form>

url.py中

urlpatterns = [    
   url(r'^admin/', admin.site.urls),    
   url(r'^hello/$', hello),    
   url(r'^addtest/$', add),    
   url(r'^search/$', search),    
   url(r'^uptest/$', update),    
   url(r'^deltest/$', delete),
]

访问：http://localhost:8000/hello/
输入想添加的内容，点击 Add，往数据库中新增一条数据

5. 读取数据库
   testdb.py中查询方法

def search(request):
      response = ""
      response1 = ""
      nameq =  request.GET.get('q')
      list = Test.objects.filter(name=nameq)
     for var in list:    
           response1 += var.name + " "
    response = response1
    return HttpResponse("<p>" + response + "</p>")

页面

<form action="/search/" method="get">    
      <input type="text" name="q">    
      <input type="submit" value="Search">
</form>