create table nfinst_audit(
operation       char(1)   not null,
stamp           timestamp not null,
userid          text      not null,
nfinstid        text      not null,
order_id        SERIAL    ,
addr            text      not null,
port            text      not null
);
--將DELETE、UPDATE、INSERT操作記錄到nfinst_audit表中
create or replace function process_nfinst_audit() returns trigger as $nfinst_audit$
begin
   if (TG_OP = 'DELETE') then
     insert into nfinst_audit(operation,stamp,userid,nfinstid,addr,port) VALUES('D',now(),user,old.nfinstid,inet_client_addr(),inet_client_port());
     return old;
   elsif (TG_OP = 'UPDATE') then
     insert into nfinst_audit(operation,stamp,userid,nfinstid,addr,port) VALUES('U',now(),user,new.nfinstid,inet_client_addr(),inet_client_port());
     return new;
   elsif (TG_OP = 'INSERT') then
     insert into nfinst_audit(operation,stamp,userid,nfinstid,addr,port) VALUES('I',now(),user,new.nfinstid,inet_client_addr(),inet_client_port());
     return new;
   end if;
   return null;
end;
$nfinst_audit$ language plpgsql;
--創建觸發器
create trigger nfinst_audit 
before insert or update or delete on nfinst
for each row execute procedure process_nfinst_audit();

def delete(self):
        for model, instances in self.data.items():
            self.data[model] = sorted(instances, key=attrgetter("pk"))
        self.sort()
        deleted_counter = Counter()
        # 開啟事務，語句塊執行結束后會根據執行結果選擇commit或者rollback
        with transaction.atomic(using=self.using, savepoint=False):
            for model, obj in self.instances_with_model():
                if not model._meta.auto_created:
                    signals.pre_delete.send(
                        sender=model, instance=obj, using=self.using
                    )
            for qs in self.fast_deletes:
                count = qs._raw_delete(using=self.using)
                deleted_counter[qs.model._meta.label] += count
            for model, instances_for_fieldvalues in six.iteritems(self.field_updates):
                query = sql.UpdateQuery(model)
                for (field, value), instances in six.iteritems(instances_for_fieldvalues):
                    query.update_batch([obj.pk for obj in instances],
                                       {field.name: value}, self.using)
            for instances in six.itervalues(self.data):
                instances.reverse()
            for model, instances in six.iteritems(self.data):
                query = sql.DeleteQuery(model)
                pk_list = [obj.pk for obj in instances]
                count = query.delete_batch(pk_list, self.using)
                deleted_counter[model._meta.label] += count
                if not model._meta.auto_created:
                    for obj in instances:
                        # 執行post_delete后置處理
                        signals.post_delete.send(
                            sender=model, instance=obj, using=self.using
                        )

post_delete = ModelSignal(providing_args=["instance", "using"], use_caching=True)

class CModel_QuerySet(models.query.QuerySet):
    def delete(self):
        # 將post_delete信號量觸發操作移到了事務外面
        for inst in self:
            post_delete.send(
                sender=self.model, instance=inst, using=None
            )
        super(CModel_QuerySet, self).delete()
class CModel_CustomManager(models.Manager):
    # custom QuerySet for snap QuerySet.update operations
    def get_queryset(self):
        return CModel_QuerySet(self.model, using=self._db)
# 自定義的Model基類
class CModelWithUpdateSignal(models.Model):
    class Meta:
        abstract = True
    # custom models.Manager for snap QuerySet.update operations
    objects = CModel_CustomManager()
    def delete(self, *args, **kwargs):
        # 將post_delete信號量觸發操作移到了事務外面
        post_delete.send(
            sender=self.__class__, instance=self, using=None
        )
        super(CModelWithUpdateSignal, self).delete(*args, **kwargs)
# 需要進行post_delete操作的Model類
class NfInstModel(CModelWithUpdateSignal):
    ……