如何在 python 2.7 django 中保存时检查对象是插入还是更新

Question

def save_model(self, request, obj, form, change):
    if self._state.adding is True:
        super(TaskAdmin, self).save_model(request, obj, form, change)
    else:
        if 'hours_per_day' in form.changed_data:
            messages.info(request, "Hours per Day has changed.")

            if date.today():
                TaskHourChange.objects.filter(date_changed=date.today()).delete()
            taskchange = TaskHourChange.objects.create(
                date_changed=date.today(), prev_hours_per_day=obj.hours_per_day, task=obj)
            taskchange.save()
        else:
            messages.info(request, "Hours per Day has not changed")
        super(TaskAdmin, self).save_model(request, obj, form, change)

我试过了，但它不起作用。我想检查对象是否被更新或插入。

Answer 1

检查是change==True（首选）还是obj.pk is None。 ModelAdmin 类是无状态的。 ModelAdmin 类的一个实例附加到site，它不会也不应该保持处理请求的状态。