how to use transaction of mysql in “save_model” and “delete_model” of django admin

问题

class DispatchAdmin(admin.ModelAdmin):

def delete_model(self, request, obj):
    a.delete()
    b.delete()

def save_model(self,request,obj,form,change):
    x.save()
    y.save()

________How can I________

how can I make the operation to the mysql database as a atomic operation by using the transaction? what should be "import",and if the action is failed, how to rollback?(notes:since I use django admin,there is no extra views.py)

来源：https://stackoverflow.com/questions/19003442/how-to-use-transaction-of-mysql-in-save-model-and-delete-model-of-django-adm