django之自定义软删除Model的方法

软删除

简单的说，就是当执行删除操作的时候，不正真执行删除操作，而是在逻辑上删除一条记录。这样做的好处是可以统计数据，可以进行恢复操作等等。

预备知识

Managers

Managers 是django models 提供的一个用于提供数据库查询操作的接口，对于Django应用程序中的每个model都会至少存在一个Manager

详细：https://docs.djangoproject.com/en/dev/topics/db/managers/

django实现软删除model

firstly，

from django.db import models
from django.db.models.query import QuerySet

# 自定义软删除查询基类
class SoftDeletableQuerySetMixin(object):
 """
 QuerySet for SoftDeletableModel. Instead of removing instance sets
 its ``is_deleted`` field to True.
 """

def delete(self):
   """
   Soft delete objects from queryset (set their ``is_deleted``
   field to True)
   """
   self.update(is_deleted=True)

class SoftDeletableQuerySet(SoftDeletableQuerySetMixin, QuerySet):
 pass

class SoftDeletableManagerMixin(object):
 """
 Manager that limits the queryset by default to show only not deleted
 instances of model.
 """
 _queryset_class = SoftDeletableQuerySet

def get_queryset(self):
   """
   Return queryset limited to not deleted entries.
   """
   kwargs = {'model': self.model, 'using': self._db}
   if hasattr(self, '_hints'):
     kwargs['hints'] = self._hints

return self._queryset_class(**kwargs).filter(is_deleted=False)

class SoftDeletableManager(SoftDeletableManagerMixin, models.Manager):
 pass

secondly，

# 自定义软删除抽象基类
class SoftDeletableModel(models.Model):
 """
 An abstract base class model with a ``is_deleted`` field that
 marks entries that are not going to be used anymore, but are
 kept in db for any reason.
 Default manager returns only not-deleted entries.
 """
 is_deleted = models.BooleanField(default=False)

class Meta:
   abstract = True

objects = SoftDeletableManager()

def delete(self, using=None, soft=True, *args, **kwargs):
   """
   Soft delete object (set its ``is_deleted`` field to True).
   Actually delete object if setting ``soft`` to False.
   """
   if soft:
     self.is_deleted = True
     self.save(using=using)
   else:
     return super(SoftDeletableModel, self).delete(using=using, *args, **kwargs)

class CustomerInfo(SoftDeletableModel):
 nid = models.AutoField(primary_key=True)
 category = models.ForeignKey("CustomerCategory", to_field="nid", on_delete=models.CASCADE, verbose_name='客户分类',
                db_constraint=False)
 company = models.CharField(max_length=64, verbose_name="公司名称")

来源：https://www.jianshu.com/p/cdae0f2acad6