django之自定义软删除Model的方法

框架(架构)  /  管理员 发布于 7年前   497

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 modelsfrom 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):  passclass 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")

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