MongoError: Performing an update on the path '_id' would modify the immutable field '_id'解决办法

 问题

最近在用mongoose更新数据库时报了这个错误：

MongoError: Performing an update on the path '_id' would modify the immutable field '_id'

 我的代码：

// 建立数据集
var movie = new mongoose.Schema({
    movieName: String,
    movieImg: String,
    movieVideo: String,
    movieDownload: String,
    movieTime: String,
    movieNumSuppose: Number,
    movieNumDownload: Number,
    movieMainPage: Boolean
});

var movieModel = mongoose.model('movie', movie);
module.exports = movieModel;

// 错误的更新代码

var updateContent = new movie({
    movieName: req.body.movieName,
    movieImg: req.body.movieImg,
    movieVideo: req.body