django框架 -3数据库连接

连接mysql数据库

Django supports MySQL 5.5 and higher.

django 数据库引擎支持sqlite3、postgresql、mysql、oracle，默认使用的是sqllite3

• 编辑 mysite/settings.py

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'django',
        'USER': 'cdy',
        'PASSWORD': 'password',
        'HOST': '127.0.0.1',
        'PORT': '3306',
    }
}

有可能报错： Error loading MySQLdb module: No module named 'MySQLdb'
解决步骤：
$ sudo pip3 install pymysql
$ sudo vim mysite/init.py //添加如下两行

 import pymysql
 pymysql.install_as_MySQLdb()

• 执行如下命令

 $ python3 manage.py  migrate

• 创建models，修改polls/models.py

from django.db import models

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')
class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

• Activating models,修改mysite/settings.py

INSTALLED_APPS = [
    'polls.apps.PollsConfig',
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
]

• 使model生效

$ python3 manage.py makemigrations polls

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• 生成建表语句

$ python3 manage.py sqlmigrate polls 0001

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• 建表

$ python3 manage.py migrate

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• 创建超级管理员

$ python3manage.pycreatesuperuser

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• 修改密码

$ pythonmanage.pychangepasswordadmin 

• 导入导出数据

$ python3 manage.py dumpdata polls > polls.json
$ python3 manage.py loaddata polls.json

• 清空数据库

$ python3 manage.py flush

• 进入数据库命令行

$ python3manage.pydbshell

更多命令，可直接python3 manage.py来查看

[caideyang@localhost mysite]$ python3 manage.py 

Type 'manage.py help ' for help on a specific subcommand.

Available subcommands:

[auth]
    changepassword
    createsuperuser

[django]
    check
    compilemessages
    createcachetable
    dbshell
    diffsettings
    dumpdata
    flush
    inspectdb
    loaddata
    makemessages
    makemigrations
    migrate
    sendtestemail
    shell
    showmigrations
    sqlflush
    sqlmigrate
    sqlsequencereset
    squashmigrations
    startapp
    startproject
    test
    testserver

[sessions]
    clearsessions

[staticfiles]
    collectstatic
    findstatic
    runserver