Django --- ORM operations

A, Django MySQL connection

1. Create a database ( note that set the character encoding data)

　　Because Django comes orm is data_first type of ORM, before using the database must be created

　　

create database db default character set utf8 collate utf8_general_ci;

 

 

 

2, settings.py project file modification provided in connection MySQL database (the Django sqllite database is used by default)

　　

DATABASES = {
    'default': {
    'ENGINE': 'django.db.backends.mysql',
    'NAME':'dbname',
    'USER': 'xxx',
    'PASSWORD': 'xxx',
    'HOST': 'localhost',
    'PORT': '3306',
    }
}

 

 

 

3, __init__py file modify project settings to connect to MySQL's default way Django

 

import pymysql
pymysql.install_as_MySQLdb()

 At this time run the program, if error: django.core.exceptions.ImproperlyConfigured: the mysqlclient 1.3.13 or newer IS required; you have have 0.9.3.

 Solution:

　　1: django down to 2.1.4 version (version use Django2.2 This problem occurs, pro-test available)

　　2: Go to the next python installation directory: . . / Site-packages / django / db / backends / mysql base.py the file, comment out the following sections (lines 35-36):

if version < (1, 3, 3):
     raise ImproperlyConfigured("mysqlclient 1.3.3 or newer is required; you have %s" % Database.__version__)

　　　　At this point still being given, the following information is given: AttributeError: 'STR' Object attribute has NO 'decode

　　　　Find operations.py file (146 lines), the decode changed to encode (146 lines):

　　　　if query is not None:
    　　　　query = query.decode(errors=‘replace‘)
　　　　　return query

　　　　改为
　　　　if query is not None:
    　　　　query = query.encode(errors=‘replace‘)
　　　　　return query

 

4, create app in terminal

 

python manage.py startapp app01

 

 

 

 

5, models.py within the app to create class

class UserInfo(models.Model):
    nid = models.BigAutoField(primary_key=True)
    username = models.CharField(max_length=32)
    password = models.CharField(max_length=64)

 

6, setting.py registered app

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'app01',　　　　　　　　　　　　#末尾添加
]

 

 

7, create a data table

Terminal run:

python manage.py makemigrations

python manage.py migrate

 

 

 

 

Two, modles.py create a table