Django与数据库

1 设置app
INSTALLED_APPS = (
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
	'blog',
)
2 首先要创建数据库：
create database csvt；
3 配置数据库settings:
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME':'csvt04',
		'USER':'root',
		'PASSWORD':'791745',
		'HOST':'',
		'PORT':'',
    }
}
4 配置models：创建了一个表blog_employee
class Employee(models.Model):
	name = models.CharField(max_length=20)
	
4 同步数据库：自动检测应用里的models
python manage.py makemigrations 
python manage.py migrate
这步做完后，数据库中的中出现表：
mysql> desc blog_employee;
+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra          |
+-------+-------------+------+-----+---------+----------------+
| id    | int(11)     | NO   | PRI | NULL    | auto_increment |
| name  | varchar(20) | NO   |     | NULL    |                |
+-------+-------------+------+-----+---------+----------------+

5 数据添加
启动解释器E:\test3\csvt03>python manage.py shell
	创建字段：
	方式一：
	from blog.models import Employee
	Employee
	ss 'blog.models.Employee'>
	emp = Employee()
	emp
	loyee: Employee object>
	emp.name = 'Alen'
	emp.save()
	
	方式二：直接在构造函数中用
	 emp = Employee(name = 'tom')
	emp.save()
	
	方式三：通过管理器直接调用
	>>> Employee.objects.create(name='zhangzhihao')
	

	查看
	>>> emps = Employee.objects.all()
	>>> emps
	[, , , ]
	>>> emps[0].name
	u'Alen'
	
	添加方法：
	class Employee(models.Model):
	name = models.CharField(max_length=20)
	
	def __unicode__(self):
		return self.name
		
	重新导入查看：
	>>> from blog.models import Employee
	>>> emps = Employee.objects.all()
	>>> emps
	[, , , ]

6 urls.py文件下添加网页
urlpatterns = [
    url(r'^admin/', include(admin.site.urls)),
	url(r'^index/$','blog.views.index'),
]

7 创建index方法：
def index(req):
	emps = Employee.objects.all()
	return render_to_response('indextest3.html',{'emps':emps})

8 创建模板，将数据库中的数据显示在页面：



    
    


{% for emp in emps%}
{{forloop.counter}} : {{emp}}
{% endfor %}




mode多对一关系：
1 models中新增方法：
from django.db import models

class Entry(models.Model):
	name = models.CharField(max_length=30)
	
	def __unicode__(self):
		return self.name
		
		
class Blog(models.Model):
	name = models.CharField(max_length=30)
	
	entry = models.ForeignKey(Entry)
	
	def __unicode__(self):
		return self.name

# Create your models here.
2 同步数据库
查看数据库结果：
mysql> describe blog_blog;
+----------+-------------+------+-----+---------+----------------+
| Field    | Type        | Null | Key | Default | Extra          |
+----------+-------------+------+-----+---------+----------------+
| id       | int(11)     | NO   | PRI | NULL    | auto_increment |
| name     | varchar(30) | NO   |     | NULL    |                |
| entry_id | int(11)     | NO   | MUL | NULL    |                |
+----------+-------------+------+-----+---------+----------------+
mysql> describe blog_entry;
+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra          |
+-------+-------------+------+-----+---------+----------------+
| id    | int(11)     | NO   | PRI | NULL    | auto_increment |
| name  | varchar(30) | NO   |     | NULL    |                |
+-------+-------------+------+-----+---------+----------------+

3 进入解释器
E:\csvt04>python manage.py shell
Python 2.7.12 (v2.7.12:d33e0cf91556, Jun 27 2016, 15:19:22) [MSC v.1500 32 bit (
Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from blog.models import Entry,Blog
>>> entry1 = Entry.objects.create(name = 'alen')
>>> entry1


>>> entry2 = Entry.objects.create(name = 'max')
>>> entry2

>>> entry3 = Entry.objects.create(name = 'carl')
>>> entry3

>>> blog1 = Blog.objects.create(name = 'alen_blog1',entry = entry1)
>>> blog1

>>> blog1.entry

>>> blog1.id
1L
>>> entry1

>>> entry1.blog_set

>>> entry1.blog_set.all()
[]
>>> blog1.entry_id
4L
>>> entry1.blog_set.all()
[]