数据库开发-Django ORM的数据库迁移

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数据库开发-Django ORM的数据库迁移

作者：尹正杰

一. Django 项目准备

1>.安装django包

pip install django=2.2.7除了使用pip安装之外，还可以从网上下载Django的压缩包自行安装。在浏览器上输入下载地址：“https://www.lfd.uci.edu/~gohlke/pythonlibs/#sendkeys”，找到如下图所示对应的Django版本下载到本地后，执行“pip install 你下载的Django软件的本地存放路径"（例如：[pip install C:\Users\yinzhengjie\softwares\Django‑2.1.4‑py3‑none‑any.whl]）

验证django是否安装成功

import django#导入django模块django.__version__#查看django的版本

2>.项目准备

django-admin startproject salary . #在当前目录下创建一个叫salary的项目./manage.py startapp employee#使用上面命令生成的管理脚本"manage.py"来创建应用

3>.打开salary/settings.py主配置文件修改数据库相关的配置

"""
Django settings for salary project.Generated by 'django-admin startproject' using Django 2.2.7.For more information on this file, see
https://docs.djangoproject.com/en/2.2/topics/settings/For the full list of settings and their values, see
https://docs.djangoproject.com/en/2.2/ref/settings/
"""import os# Build paths inside the project like this: os.path.join(BASE_DIR, ...)
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/2.2/howto/deployment/checklist/# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = 'dbeqm&74uxuz(@#7)+cau6x$&3&3t6lq9q4iqjo=o92k0jv6^8'# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = TrueLOGGING = {
'version': 1,
'disable_existing_loggers': False,
'handlers': {
'console': {
'class': 'logging.StreamHandler',
},
},
'loggers': {
'django.db.backends': {
'handlers': ['console'],
'level': 'DEBUG',
},
},
}ALLOWED_HOSTS = []# Application definitionINSTALLED_APPS = [
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'employee'
]MIDDLEWARE = [
'django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
]ROOT_URLCONF = 'salary.urls'TEMPLATES = [
{
'BACKEND': 'django.template.backends.django.DjangoTemplates',
'DIRS': [],
'APP_DIRS': True,
'OPTIONS': {
'context_processors': [
'django.template.context_processors.debug',
'django.template.context_processors.request',
'django.contrib.auth.context_processors.auth',
'django.contrib.messages.context_processors.messages',
],
},
},
]WSGI_APPLICATION = 'salary.wsgi.application'# Database
# https://docs.djangoproject.com/en/2.2/ref/settings/#databasesDATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'NAME': 'school',
'USER': 'jason',
'PASSWORD': 'yinzhengjie',
'HOST': '172.30.1.101',
'PORT': '',
}
}# Password validation
# https://docs.djangoproject.com/en/2.2/ref/settings/#auth-password-validatorsAUTH_PASSWORD_VALIDATORS = [
{
'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
},
{
'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
},
{
'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
},
{
'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
},
]# Internationalization
# https://docs.djangoproject.com/en/2.2/topics/i18n/LANGUAGE_CODE = 'zh-hans'TIME_ZONE = 'Asia/Shanghai'USE_I18N = TrueUSE_L10N = TrueUSE_TZ = True# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/2.2/howto/static-files/STATIC_URL = '/static/'

salary/settings.py文件内容戳这里

注册应用:

数据库配置:

时区配置:

配置Django的日志级别:

4>.Python支持的MySQL驱动

使用过Django1.11.x的小伙伴应该知道，由于Django默认是使用MySQLDB数据库驱动连接MySQL，不过该驱动不支持python 3.x版本。因此我们可以使用pymysql来代替默认的MySQLDB，编辑根项目路径下的"__init__.py",添加如下图所示的内容即可。本篇博客使用的是Django 2.2.x版本，该版本Django默认使用的是mysqlclient(在MySQLdb的基础上，增加了对Python 3的支持)驱动，因此无需做其他配置，只需要安装mysqlclient对应的模块即可。

二.数据库迁移

1>.编写Model类

from django.db import models # Create your models here.
from django.db import models
class Employee(models.Model):
class Meta:
db_table = 'employees' emp_no = models.IntegerField(primary_key=True)
birth_date = models.DateField(null=False)
first_name = models.CharField(null=False, max_length=14)
last_name = models.CharField(null=False, max_length=16)
gender = models.SmallIntegerField(null=False)
hire_date = models.DateField(null=False) def __repr__(self):
return "<Employee: {} {} {}>".format(
self.emp_no,
self.first_name,
self.last_name
) __str__ = __repr__

employee.models.py文件内容