Get error Call to a member function isNew() on null during upgrade to 3.1.0

Problem/Motivation

Get error message during updb
> [error] Call to a member function isNew() on null
> [error] Update failed: rate_update_9001
[error] Update aborted by: rate_update_9001

Steps to reproduce

upgrade rate form 3.0.1 to 3.1.0
drush updb get error

Proposed resolution

add $view not empry judgement logic

Remaining tasks

User interface changes

API changes

Data model changes