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入门笔记翻译整理自：https://docs.djangoproject.com/en/1.8/topics/
*该笔记将对各个模块进行单独介绍
*Model&Database
模型是数据的唯一信息源，它指示了数据的域（fields）和行为（behaviors）。每个模型都对应一个数据库表。
①每个模型都是django.db.models.Model的子类；②模型的每个属性代表了数据库的域；③数据库入口API，参考making queries部分。
比如，
1 from django.db import models 2 3 class Person(models.Model): 4 first_name = models.CharField(max_length=30) 5 last_name = models.CharField(max_length=30)
对应的数据库表：
1 CREATE TABLE myapp_person ( 2 "id" serial NOT NULL PRIMARY KEY, 3 "first_name" varchar(30) NOT NULL, 4 "last_name" varchar(30) NOT NULL 5 );
使用模型：
INSTALLED_APPS = ( #... ‘myapp‘, #... )
Django使用Field类来决定：①数据库的列类型（如INTEGER, VARCHAR）；②HTML widget（如<input type="text">,<select>）
各种Field的属性不尽相同，但是它们也有一些共同的可选属性。null=True，将空值存储为NULL，默认为False；blank=True，允许空值，默认为False；choices，举例如下：
1 from django.db import models 2 3 class Person(models.Model): 4 SHIRT_SIZES = ( 5 (‘S‘, ‘Small‘), 6 (‘M‘, ‘Medium‘), 7 (‘L‘, ‘Large‘), 8 ) 9 name = models.CharField(max_length=60) 10 shirt_size = models.CharField(max_length=1, choices=SHIRT_SIZES)
1 >>> p = Person(name="Fred Flintstone", shirt_size="L") 2 >>> p.save() 3 >>> p.shirt_size 4 ‘L‘ 5 >>> p.get_shirt_size_display() 6 ‘Large‘
default，定义field的默认值；help_text，在表单widget中显示帮助文档；primary_key=True，相应Field为主键，否则会自动生成主键，主键不可更改，比如：
1 from django.db import models 2 3 class Fruit(models.Model): 4 name = models.CharField(max_length=100, primary_key=True)
1 >>> fruit = Fruit.objects.create(name=‘Apple‘) 2 >>> fruit.name = ‘Pear‘ 3 >>> fruit.save() 4 >>> Fruit.objects.values_list(‘name‘, flat=True) 5 [‘Apple‘, ‘Pear‘]
unique=True，相应Field的值必须为独一无二的。
大多数域可以直接设置域别名（Verbose field names）：
1 # verbose name is "person‘s first name" 2 first_name = models.CharField("person‘s first name", max_length=30) 3 # verbose name is "first name" 4 first_name = models.CharField(max_length=30)
ForeighKey，ManyToManyField和OneToOneField需要使用verbose_name参数，来设置域别名：
1 poll = models.ForeignKey(Poll, verbose_name="the related poll") 2 sites = models.ManyToManyField(Site, verbose_name="list of sites") 3 place = models.OneToOneField(Place, verbose_name="related place")
数据库中常见的三种关系为：多对一，多对多，一对一。
①多对一
1 from django.db import models 2 3 class Manufacturer(models.Model): 4 # ... 5 pass 6 7 class Car(models.Model): 8 manufacturer = models.ForeignKey(Manufacturer) 9 # ...
②多对多
1 from django.db import models 2 3 class Topping(models.Model): 4 # ... 5 pass 6 7 class Pizza(models.Model): 8 # ... 9 toppings = models.ManyToManyField(Topping)
或者
1 from django.db import models 2 3 class Person(models.Model): 4 name = models.CharField(max_length=128) 5 6 def __str__(self): # __unicode__ on Python 2 7 return self.name 8 9 class Group(models.Model): 10 name = models.CharField(max_length=128) 11 members = models.ManyToManyField(Person, through=‘Membership‘) 12 13 def __str__(self): # __unicode__ on Python 2 14 return self.name 15 16 class Membership(models.Model): 17 person = models.ForeignKey(Person) 18 group = models.ForeignKey(Group) 19 date_joined = models.DateField() 20 invite_reason = models.CharField(max_length=64)
③一对一
1 from django.db import models 2 3 class Place(models.Model): 4 name = models.CharField(max_length=50) 5 address = models.CharField(max_length=80) 6 7 def __str__(self): # __unicode__ on Python 2 8 return "%s the place" % self.name 9 10 class Restaurant(models.Model): 11 place = models.OneToOneField(Place, primary_key=True) 12 serves_hot_dogs = models.BooleanField(default=False) 13 serves_pizza = models.BooleanField(default=False) 14 15 def __str__(self): # __unicode__ on Python 2 16 return "%s the restaurant" % self.place.name
需要先导入相应模块：
1 from django.db import models 2 from geography.models import ZipCode 3 4 class Restaurant(models.Model): 5 # ... 6 zip_code = models.ForeignKey(ZipCode)
meta用于接收一切不是Field的数据。
1 from django.db import models 2 3 class Ox(models.Model): 4 horn_length = models.IntegerField() 5 6 class Meta: 7 ordering = ["horn_length"] 8 verbose_name_plural = "oxen"
Future work:
model field reference; writing custom model fields
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原文地址：http://www.cnblogs.com/py-drama/p/4600969.html
