django之软删除model

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，继承SoftDeletableModel抽象基类

class CustomerInfo(SoftDeletableModel):  
     company =models.CharField(max_length=64,verbose_name="公司名称")