保存时,检查字段是否更改

在 admin 中
form.changed_data 是一个列表，存有真实改变的字段名称

    def save_model(self, request, obj, form, change):
        if change and form.changed_data:
            print('change!!!')
        else:
            print('no  change!!!')
        super(ScenicAdmin, self).save_model(request, obj, form, change)

在 model 中

class MyModel(models.Model):
    f1 = models.CharField(max_length=1)
    def save(self, *args, **kw):
        if self.pk is not None:
            orig = MyModel.objects.get(pk=self.pk)
            if orig.f1 != self.f1:
                print 'f1 changed'
        super(MyModel, self).save(*args, **kw)

在 form 中

class MyModelForm(forms.ModelForm):
    def clean(self):
        cleaned_data = super(ProjectForm, self).clean()
        #if self.has_changed():  # new instance or existing updated (form has data to save)
        if self.instance.pk is not None:  # new instance only
            if self.instance.f1 != cleaned_data['f1']:
                print 'f1 changed'
        return cleaned_data
    class Meta:
        model = MyModel
        exclude = []