一：Django Model

Create a model:

1. Regularly create models

   1. Configure the database information in the setting.py file

      # Database
      # https://docs.djangoproject.com/en/2.1/ref/settings/#databases
      
      DATABASES = {
          'default': {
              'ENGINE': 'django.db.backends.mysql',
              'HOST': MYSQL_ADDRESS_PRO,
              'PORT': '3306',
              'NAME': 'db_name',
              'USER': MYSQL_ACCOUND_PRO,
              'PASSWORD': MYSQL_PASS_PRO,
          }
      }

   2. Create new models in the models.py file in your django-app

      from django.db import models
      
      
      class ZkysBaseModel(models.Model):
          # 所有model都有的字段，基类
          is_delete = models.BooleanField(default=False, db_index=True)
          c_time = models.DateTimeField(auto_now_add=True)
          u_time = models.DateTimeField(auto_now=True)
      
          # 类中在定义一个类就代表是配置，约定俗成都叫Meta
          class Meta:
              # 基表必须设置abstract，基表就是给普通Model类继承使用的，设置了abstract就不会完成数据库迁移完成建表
              abstract = True
      
      
      class NotDeletedManager(models.Manager):
          """
          @description  :重写模型管理器的getqueryset方法,这样get请求就自动过滤掉is_delete为True
                         的字段了,sure,你可以可以定义你自己的规则。
          ---------
          @param  :
          -------
          @Returns  :
          -------
          """
          def get_queryset(self):
              return models.Manager.get_queryset(self).filter(is_delete=False)
      
      
      class BladeNumberTableModel(ZkysBaseModel):
          task_id = models.CharField(unique=True, max_length=50, blank=True, null=True)
          blade_one = models.CharField(max_length=255, default="", help_text='')
          blade_two = models.CharField(max_length=255, default="", help_text='')
          blade_three = models.CharField(max_length=255, default="", help_text='')
          # 添加逻辑外键，不改变mysql的表结构，但是可以用orm关联查询，db_constraint=False就是实现了这个功能
          fault_type_code = models.ForeignKey(to='FaultTypeManage', to_field='fault_type_code', on_delete=models.SET_NULL, db_constraint=False, null=True, blank=True, db_column="fault_type_code")
          objects = NotDeletedManager()
      
          class Meta:
              managed = True
              db_table = 'blade_number_table'

2. Convert existing database structure to model in Django

   1. python .\manage.py inspectdb > my_modela_app/models.py The automatically generated model may be different from the actual one, but it doesn’t matter, it will be resolved during the first migration

   2. python .\manage.py makemigrations generate migration files

   3. python .\manage.py migrate --fake Because it is a transferred model, normal migration will definitely report an error, and I hope django thinks this is the result of the existing database, so add --fake for the first migration (the database ignores this times migrate)

   4. The subsequent operations will be the same as the normal operation model orm process

   5. Registering django_comment_migrate in install_app during migration will help us arrange the field comments in the model into the mysql table