刚开始学django，用的是django book 2.0的教程。感觉这个教程比官方文档更容易入门，但因为这个教程针对的版本有些低，而我下的是django 1.8的版本。所以还是边看边练的时候还是有些坑啊。把遇到的问题在这里记录下

　　一、激活app

　　在mysite目录下,建立新的app。

$ python manage.py startapp books

 　在setting.py中，找到INSTALLED_APPS，把新建的APP，books加进去，如下。《django book2.0》中，是"mysite.books",在1.8中这样加会报错，找不到该应用

INSTALLED_APPS = (

　　 #'django.contrib.admin',

　　 #'django.contrib.auth',

　   #'django.contrib.contenttypes',

　　#'django.contrib.sessions',

　　#'django.contrib.messages',

　　#'django.contrib.staticfiles',

　　'books', )

 二、建立模型

 1.编辑完models.py后，验证模型是否准确。应使用python manage.py check。

$ python manage.py validate

/usr/local/lib/python2.7/distpackages/Django-1.8.8-py2.7.egg/django/core/management/commands/validate.py:15: RemovedInDjango19Warning: "validate" has

been deprecated in favor of "check". RemovedInDjango19Warning)

 2.查看模型models.py会在数据库中运行怎样的sql,使用  python manage.py sqlall books 会报如下错误

CommandError: App 'books' has migrations. Only the sqlmigrate and sqlflush commands can be used when an app has migrations.

正确的做法是

$ python manage.py makemigrations books

Migrations for 'books': 0001_initial.py: - Create model Author - Create model Book - Create model Publisher - Add field publisher to book

$ python manage.py sqlmigrate books 0001

BEGIN; CREATE TABLE `books_author` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY, `name` varchar(60) NOT NULL, `email` varchar(254) NOT NULL); .....

$ python manage.py migrate

Operations to perform: Apply all migrations: books Running migrations: Rendering model states... DONE Applying books.0001_initial... OK