軟刪除

     簡單的說，就是當執行刪除操作的時候，不正真執行刪除操作，而是在邏輯上刪除一條記錄。這樣做的好處是可以統計資料，可以進行恢復操作等等。

預備知識

Managers

    Managers 是django models 提供的一個用於提供資料庫查詢操作的介面，對於Django應用程式中的每個model都會至少存在一個Manager

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

django實現軟刪除model

firstly，

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

# 自定義軟刪除查詢基類
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，繼承SoftDeletableModel抽象基類

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