Django模块笔记【六】

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

*migration&Managing files&Testing in Django

1. migration的命令

migrate命令负责应用migrations，同时也负责撤销migrations以及查看他们的状态。

makemigrations基于对模型的改变，创建新的migrations。

sqlmigrate为migration显示SQL语句。

2. 模型中的文件

from django.db import models

class Car(models.Model):
    name = models.CharField(max_length=255)
    price = models.DecimalField(max_digits=5, decimal_places=2)
    photo = models.ImageField(upload_to='cars')

 以上模型中，photo是文件。

>>> car = Car.objects.get(name="57 Chevy")
>>> car.photo
<ImageFieldFile: chevy.jpg>
>>> car.photo.name
'cars/chevy.jpg'
>>> car.photo.path
'/media/cars/chevy.jpg'
>>> car.photo.url
'http://media.example.com/cars/chevy.jpg

3. Django中的测试

from django.test import TestCase
from myapp.models import Animal

class AnimalTestCase(TestCase):
    def setUp(self):
        Animal.objects.create(name="lion", sound="roar")
        Animal.objects.create(name="cat", sound="meow")

    def test_animals_can_speak(self):
        """Animals that can speak are correctly identified"""
        lion = Animal.objects.get(name="lion")
        cat = Animal.objects.get(name="cat")
        self.assertEqual(lion.speak(), 'The lion says "roar"')
        self.assertEqual(cat.speak(), 'The cat says "meow"')

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