Django project mysql database connection and table creation

Database Connectivity

1. First, make sure we have generated a basic Django project file with the following directory structure:
   
   Reference link for the specific construction process: https://blog.csdn.net/David_house/article/details/131188889?spm=1001.2014.3001.5502
2. Find the settings file under the project, open it, and modify the relevant content

• Add the application name (my application name here is app, I added app in the last line)

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'app'
]

• Modify the database connection information.
  I am using the mysql database here. 'NAME' is followed by the database name you want to use.

DATABASES = {
    
    
    'default':
    {
    
    
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'dfds',
        'HOST':'127.0.0.1',
        'PORT':3306,
        'USER':'root',
        'PASSWORD':'123456'
    }
}

3. Open the init file in the app directory. Note that it is not the init file in migrations. Add the following content:

import pymysql
pymysql.install_as_MySQLdb()

Table creation

1. Open the models.py file and add the information of the tables you want to create. For example, I want to create three tables here. The specific contents are as follows:

# Create your models here.
class Users(models.Model):
	#前面的变量名会默认生成为表中的列名，如果想单独设置可以通过属性db_column=''
	#当使用CharField时，一定要通过max_length来设置一下最大长度
    id=models.AutoField('用户id',primary_key=True)  #primary_key为True时表示该列是主键
    email=models.CharField('用户邮箱',max_length=50,null=False) #null=False表示不为空
    password = models.CharField('用户登录密码',max_length=8,null=False)
    class Meta:
        db_table='user'  #设置对应的表名

class Test(models.Model):
    sample_id = models.AutoField('数据唯一标识符', primary_key=True)
    classification = models.IntegerField('分类类别', null=False)
    features = models.CharField('特征',max_length=1000)
    #ForeignKey来指定外键，第一个参数是关联的表，第二个参数是表连接的方式
    u_id = models.ForeignKey(Users, on_delete=models.CASCADE)
    class Meta:
        db_table = 'test'

class getModel(models.Model):
    m_id = models.AutoField('模型的唯一标识符', primary_key=True)
    model = models.CharField('模型文件保存路径',max_length=1000, null=False)
    sample_id = models.ForeignKey(Test,on_delete=models.CASCADE)
    class Meta:
        db_table = 'model'

2. Open the terminal, enter the directory where the manage.py file is located ,
   and execute the command python manage.py makemigrationsto generate the corresponding model. The execution results are as follows:

3. Execute the command python manage.py migrateto generate the corresponding data table. The execution results are as follows:

Finally, we went to the database to check and found that the table was automatically generated:
the last three tables were designed by ourselves, and the others are needed when the Django project is running. data sheet