十分钟实现Django在线教育平台数据迁移

一.搭建虚拟环境-virtualenv

1. 为什么需要使用virtualenv ？

虚拟环境的作用是创建一个独立的python环境，将每一个应用的环境独立开来，解决了不同应用及多版本之间的冲突问题。在开发的日常中，我们会将python及配套的应用全部安装在电脑上，所创建的应用都是使用这一套环境，这就很容易出现不同应用之间环境冲突，也会出现各种配置因版本的差异而不兼容，virtualenv将每一个应用的环境独立开来，并提供一套创建、复制、切换等管理虚拟环境的工具，使得环境配置变的简单。

3. 安装虚拟环境管理器virtualenvwrapper

pip install virtualenvwrapper

这个命令只适用mac，安装成功后需要为该应用配置环境变量，

MacBook-Pro-2:python-works yucanghai$ export WORKON_HOME=~/Users/yucanghai/python-works/virtual_envs_works

虚拟环境的环境变量配置完成，我们通过source命令来执行virtualenvwrapper.sh即可为该虚拟项目安装所需的环境，

MacBook-Pro-2:~ yucanghai$ sudo find / -name virtualenvwrapper.shfind: /dev/fd/yucanghai: No such file or directoryfind: /dev/fd/yucanghai: No such file or directory/usr/local/bin/virtualenvwrapper.shdawendeMacBook-Pro-2:~ yujiafeng$ source /usr/local/bin/virtualenvwrapper.sh

命令中sudo find命令可以查找到virtualenvwrapper.sh所在的目录，通过source命令即可为该虚拟环境安装所需的配置，至此，我们的虚拟环境配置已经完成。

保存该配置，再重启终端，输入workon命令，发现可以正常使用了。

二.django实现在线教育平台之数据迁移

打开terminal，输入workon命令即可查看该电脑上所有创建的虚拟环境(在 django搭建虚拟环境-virtualenv 最后，我们讲了需要环境变量的方法，如果没有配置环境变量，你会发现这里会找不到workon命令)；

输入命令 mkvirtualenv icoachu 创建一个名为icoachu的虚拟环境；

输入命令 workon icoachu 进入到icoachu虚拟环境中；

输入命令 django-admin startproject icoachu_python 创建一个名为icoachu_python的django项目；

6.在apps目录下新建四个app，分别是users、courses、organization、operation，并在项目的setting中添加四个应用。

(icoachu) MacBook-Pro-2:icoachu_python yucanghai$ lsapps icoachu_python logs manage.py static upload(icoachu) MacBook-Pro-2:icoachu_python yucanghai $ python3 manage.py startapp users(icoachu) MacBook-Pro-2:icoachu_python yucanghai $ python3 manage.py startapp courses(icoachu) MacBook-Pro-2:icoachu_python yucanghai $ python3 manage.py startapp organization(icoachu) MacBook-Pro-2:icoachu_python yucanghai $ python3 manage.py startapp operation(icoachu) MacBook-Pro-2:icoachu_python yucanghai $ lsapps icoachu_python logs manage.py static upload(icoachu) MacBook-Pro-2:icoachu_python yucanghai $ python3 manage.py runserverPerforming system checks...System check identified no issues (0 silenced).You have 13 unapplied migration(s). Your project may not work properly until you apply the migrations for app(s): admin, auth, contenttypes, sessions.Run 'python manage.py migrate' to apply them.December 07, 2017 - 06:43:13Django version 1.11.4, using settings 'icoachu_python.settings'Starting development server at http://127.0.0.1:8000/Quit the server with CONTROL-C.[07/Dec/2017 06:43:26] "GET / HTTP/1.1" 200 1716

2. 各app中数据models的实现

在 实战项目：

中我们已经对表的字端进行了设计，这里我们直接用代码实现：

首先，我们先看users下models的实现

from django.db import models

from datetime import datetime

# Create your models here.

class Users(AbstractUser):

nick_name = models.CharField(max_length=50, default=u'', verbose_name=u'昵称')

birth = models.DateField(verbose_name=u'生日', null=True, blank=True)

gender = models.CharField(max_length=5, choices=(('male', u'男'), ('female', u'女')),

default='female', verbose_name=u'性别')

address = models.CharField(max_length=100, default='', verbose_name=u'地址')

mobile = models.CharField(max_length=11, null=True, blank=True, verbose_name=u'手机号码')

avatar = models.ImageField(max_length=100, upload_to=u'avatar/%Y/%m', default=u'avatar/default.png',

verbose_name=u'用户头像')

class Meta:

verbose_name = u'用户信息表'

verbose_name_plural = verbose_name

def __unicode__(self):

return self.username

class EmailVerifyCode(models.Model):

code = models.CharField(max_length=20, verbose_name=u'验证码')

email = models.EmailField(max_length=50, verbose_name=u'邮箱地址')

send_type = models.CharField(max_length=10, choices=(('register', u'注册'), ('forgot', u'忘记密码')))

send_time = models.DateTimeField(default=datetime.now())

class Meta:

verbose_name = u'邮箱验证码'

verbose_name_plural = verbose_name

class Banner(models.Model):

title = models.CharField(max_length=100, verbose_name=u'标题')

image = models.ImageField(max_length=100, verbose_name=u'图片地址', upload_to='banner/%Y/%m')

url = models.CharField(max_length=100, verbose_name=u'跳转地址')

add_time = models.DateTimeField(default=datetime.now(), verbose_name=u'添加时间')

index = models.IntegerField(default=100, verbose_name=u'排列顺序')

class Meta:

verbose_name = u'轮播图'

verbose_name_plural = verbose_name

接下来，我们来实现courses的models：

from django.db import models

from datetime import datetime

# Create your models here.

class Courses(models.Model):

name = models.CharField(max_length=50, verbose_name=u'课程名称')

desc = models.CharField(max_length=300, verbose_name=u'课程描述')

detail = models.TextField(verbose_name=u'课程详情')

degree = models.CharField(max_length=2, verbose_name=u'课程难度',

choices=(('cj', u'初级'), ('zj', u'中级'), ('gj', u'高级')), default='cj')

learn_duration = models.IntegerField(max_length=2, verbose_name=u'学习时长(分钟)', default=0)

student_num = models.IntegerField(default=0, verbose_name=u'学生人数')

favorates_num = models.IntegerField(default=0, verbose_name=u'收藏人数')

image = models.ImageField(max_length=200, upload_to='courses/%Y/%m', verbose_name=u'封面图')

click_num = models.IntegerField(default=0, verbose_name=u'点击数')

add_time = models.DateTimeField(default=datetime.now(), verbose_name=u'添加时间')

class Meta:

verbose_name = u'课程信息'

verbose_name_plural = verbose_name

class Lesson(models.Model):

course = models.ForeignKey(Courses, verbose_name=u'所属课程')

name = models.CharField(max_length=100, verbose_name=u'章节名称')

add_time = models.DateTimeField(default=datetime.now(), verbose_name=u'添加时间')

class Meta:

verbose_name = u'章节信息'

verbose_name_plural = verbose_name

class Video(models.Model):

lesson = models.ForeignKey(Lesson, verbose_name=u'所属章节')

name = models.CharField(max_length=100, verbose_name=u'视频名称')

add_time = models.DateTimeField(default=datetime.now(), verbose_name=u'添加时间')

class Meta:

verbose_name = u'视频信息'

verbose_name_plural = verbose_name

class CourseResource(models.Model):

course = models.ForeignKey(Courses, verbose_name=u'所属课程')

name = models.CharField(max_length=100, verbose_name=u'课程资源名')

add_time = models.DateTimeField(default=datetime.now(), verbose_name=u'添加时间')

download = models.FileField(max_length=100, upload_to='course/resource/%Y/%m', verbose_name=u'课程资源文件下载地址')

class Meta:

verbose_name = u'课程资源'

verbose_name_plural = verbose_name

现在，我们来实现organization的models数据字段设计：

from django.db import models

from datetime import datetime

# Create your models here.

class CityDict(models.Model):

name = models.CharField(max_length=20, verbose_name=u'城市名称')

desc = models.CharField(max_length=200, verbose_name=u'城市描述')

add_time = models.DateTimeField(default=datetime.now(), verbose_name=u'添加时间')

class Meta:

verbose_name = u'城市信息'

verbose_name_plural = verbose_name

class CourseOrg(models.Model):

name = models.CharField(max_length=50, verbose_name=u'机构名称')

desc = models.TextField(verbose_name=u'机构描述')

favorites_num = models.IntegerField(default=0, verbose_name=u'收藏人数')

click_num = models.IntegerField(default=0, verbose_name=u'点击数')

image = models.ImageField(max_length=200, upload_to='courses/%Y/%m', verbose_name=u'封面图')

address = models.CharField(max_length=150, verbose_name=u'机构地址')

add_time = models.DateTimeField(default=datetime.now, verbose_name=u'添加时间')

class Meta:

verbose_name = u'机构课程'

verbose_name_plural = verbose_name

class Teacher(models.Model):

org = models.ForeignKey(CourseOrg, verbose_name=u'所属机构')

name = models.CharField(max_length=50, verbose_name=u'教师名')

work_years = models.IntegerField(default=0, verbose_name=u'工作年限')

work_company = models.CharField(max_length=50, verbose_name=u'就职公司')

work_position = models.CharField(max_length=50, verbose_name=u'工作职位')

work_point = models.CharField(max_length=100, verbose_name=u'教学特点')

favorites_num = models.IntegerField(default=0, verbose_name=u'收藏人数')

click_num = models.IntegerField(default=0, verbose_name=u'点击数')

add_time = models.DateTimeField(default=datetime.now, verbose_name=u'添加时间')

class Meta:

verbose_name = u'教师信息'

verbose_name_plural = verbose_name

最后，我们来实现operation下models的数据设计：

# coding=utf-8

from django.db import models

from datetime import datetime

from apps.users.models import UserProfile

from apps.courses.models import Courses

# Create your models here.

class UserAsk(models.Model):

name = models.CharField(max_length=50, verbose_name=u'姓名')

mobile = models.CharField(max_length=11, verbose_name=u'手机号码')

course_name = models.CharField(max_length=50, verbose_name=u'咨询的课程名')

add_time = models.DateTimeField(default=datetime.now, verbose_name=u'添加时间')

class Meta:

verbose_name = u'用户咨询'

verbose_name_plural = verbose_name

class CourseComment(models.Model):

user = models.ForeignKey(UserProfile, verbose_name=u'用户')

course = models.ForeignKey(Courses, verbose_name=u'课程')

comments = models.CharField(max_length=200, verbose_name=u'评论内容')

add_time = models.DateTimeField(default=datetime.now, verbose_name=u'评论时间')

class Meta:

verbose_name = u'课程评论'

verbose_name_plural = verbose_name

class UserFavorite(models.Model):

user = models.ForeignKey(UserProfile, verbose_name=u'用户')

fav_type = models.IntegerField(choices=((1, '课程'), (2, '教师'), (3, '授课机制')), default=1, verbose_name=u'收藏类型')

fav_id = models.IntegerField(default=0, verbose_name=u'收藏类型')

add_time = models.DateTimeField(default=datetime.now, verbose_name=u'添加时间')

class Meta:

verbose_name = u'用户收藏'

verbose_name_plural = verbose_name

class UserMessage(models.Model):

user = models.IntegerField(default=0, verbose_name=u'接收id')

message = models.CharField(max_length=500, verbose_name=u'消息内容')

has_read = models.BooleanField(default=False, verbose_name=u'是否已读')

add_time = models.DateTimeField(default=datetime.now, verbose_name=u'添加时间')

class Meta:

verbose_name = u'用户消息'

verbose_name_plural = verbose_name

class UserCourse(models.Model):

user = models.ForeignKey(UserProfile, verbose_name=u'用户')

course = models.ForeignKey(Courses, verbose_name=u'课程')

add_time = models.DateTimeField(default=datetime.now, verbose_name=u'添加时间')

class Meta:

verbose_name = u'用户学习的课程'

verbose_name_plural = verbose_name

Pillow是python下的一个图像处理库，我们通过安装一下：

MacBook-Pro-2:icoachu_python yucanghai$ sudo pip install PillowPassword:The directory '/Users/yucanghai/Library/Caches/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.The directory '/Users/yucanghai/Library/Caches/pip' or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.Collecting Pillow Downloading Pillow-4.3.0-cp27-cp27m-macosx_10_6_intel.macosx_10_9_intel.macosx_10_9_x86_64.macosx_10_10_intel.macosx_10_10_x86_64.whl (3.5MB) 100% |████████████████████████████████| 3.6MB 190kB/s Collecting olefile (from Pillow)Installing collected packages: olefile, Pillow Successfully installed Pillow-4.3.0 olefile-0.44

以上两种方案都可以解决上述问题，可选择其中任何一种。接下来我们实现数据迁移：

MacBook-Pro-2:icoachu_python yucanghai$ python manage.py makemigrationsMigrations for 'courses': apps/courses/migrations/0001_initial.py - Create model CourseResource - Create model Courses - Create model Lesson - Create model Video - Add field course to courseresourceMigrations for 'operation': apps/operation/migrations/0001_initial.py - Create model CourseComment - Create model UserAsk - Create model UserCourse - Create model UserFavorite - Create model UserMessage apps/operation/migrations/0002_auto_20171208_0807.py - Add field user to userfavorite - Add field course to usercourse - Add field user to usercourse - Add field course to coursecomment - Add field user to coursecommentMigrations for 'users': apps/users/migrations/0001_initial.py - Create model UserProfile - Create model Banner - Create model EmailVerifyCodeMigrations for 'organization': apps/organization/migrations/0001_initial.py - Create model CityDict - Create model CourseOrg - Create model TeacherdawendeMacBook-Pro-2:icoachu_python yucanghai$ python manage.py migrateOperations to perform: Apply all migrations: admin, auth, contenttypes, courses, operation, organization, sessions, usersRunning migrations: Applying contenttypes.0001_initial... OK Applying contenttypes.0002_remove_content_type_name... OK Applying auth.0001_initial... OK Applying auth.0002_alter_permission_name_max_length... OK Applying auth.0003_alter_user_email_max_length... OK Applying auth.0004_alter_user_username_opts... OK Applying auth.0005_alter_user_last_login_null... OK Applying auth.0006_require_contenttypes_0002... OK Applying auth.0007_alter_validators_add_error_messages... OK Applying auth.0008_alter_user_username_max_length... OK Applying users.0001_initial... OK Applying admin.0001_initial... OK Applying admin.0002_logentry_remove_auto_add... OK Applying courses.0001_initial... OK Applying operation.0001_initial... OK Applying operation.0002_auto_20171208_0807... OK Applying organization.0001_initial... OK Applying sessions.0001_initial... OKMacBook-Pro-2:icoachu_python yucanghai$

执行完上述操作，你会发现在mysql下创建了很多的表，至此数据迁移完成。