Model Cakephp将值保存到数据库中

我有一张电影表和一张评级表。电影的分级表，电影只有一个分级。我想增加“投票计数”字段。代码如下

public function set_ratings($movieId, $value){
    $this->Movie->id = $movieId;
    $rateMovie = $this->Movie->read();
    $oldNoOfVotes = $rateMovie['Rating']['number_of_votes'];
    debug($oldNoOfVotes);
    $newNoOfVotes = ++$oldNoOfVotes;
    $newVoteCount = $rateMovie['Rating']['vote_count'] + $value;
    $newAverageRating = $newVoteCount / $newNoOfVotes;
    debug($oldNoOfVotes);
    debug($newNoOfVotes);
    $this->request->data['Rating']['id'] = $rateMovie['Rating']['id'];
    $this->request->data['Rating']['number_of_votes'] = $newNoOfVotes;
    $this->request->data['Rating']['vote_count'] = $newVoteCount;
    $this->request->data['Rating']['average_rating'] = $newAverageRating;
    //$this->request->data['Rating']['id'] =  $rateMovie['Rating']['id'];
    debug($newNoOfVotes);
    $this->Movie->Rating->save($this->request->data);
    debug($newNoOfVotes);
}

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我面临的问题是，如果“投票计数”是15，当我增加它并调试时，值是16，但在DB中，它被保存为18。原因是什么

您确定没有调用该函数两次或两次以上吗？或者数据库引擎会增加它的增量（类似于更新增量SQL语句）

您调试过（$newVoteCount）？