mongoDB中的数组更新

Question

我有这样的猫鼬模式：

var mySchema = new mongoose.Schema({
    user: String,
    photos: [{
       url: String,
       thumbnail: String,
       time: Date,
       mainPhoto: Boolean
    }]
});

现在，我想创建一个“setMainPhoto”函数 - 对于给定的 id - 将 mainPhoto 标志设置为 true，并将其他照片设置为 false。 有这样的文件：

{
"_id": {
    "$oid": "56269dea07a455920a21bca7"
},
"user": "someUser",
"photos": [
    {
        "time": {
            "$date": "2015-05-25T08:37:56.000Z"
        },
        "thumbnail": "https://s3-eu-west-1.amazonaws.com/...jpg",
        "url": "https://s3-eu-west-1.amazonaws.com/...jpg",
        "_id": {
            "$oid": "56269e2e07a455920a21bcab"
        },
        "mainPhoto": false
    },
    {
        "time": {
            "$date": "2015-05-25T09:27:17.000Z"
        },
        "thumbnail": "https://s3-eu-west-1.amazonaws.com/...jpg",
        "url": "https://s3-eu-west-1.amazonaws.com/...jpg",
        "_id": {
            "$oid": "56269e3507a455920a21bcae"
        },
        "mainPhoto": true
    },
    {
        "time": {
            "$date": "2015-05-25T09:27:17.000Z"
        },
        "thumbnail": "https://s3-eu-west-1.amazonaws.com/...jpg",
        "url": "https://s3-eu-west-1.amazonaws.com/...jpg",
        "_id": {
            "$oid": "56269e3507a455920a21bcaf"
        },
        "mainPhoto": false
    }
 ]}

我正在尝试使用猫鼬保存功能来做到这一点：

var myModel = mongoose.model('myCollection', mySchema);
myModel.find({user:params.user,_id:params.documentId}, function(err,data){
    var newMyModel = new myModel(data[0]);

    for(var i=0; i<newMyModel.photos.length; i++){
        if(newMyModel.photos[i]._id == params.photoId){
            newMyModel.photos[i].mainPhoto = true;
        }else{
            newMyModel.photos[i].mainPhoto = false;
        }
    }

    return newTrack.save(function(err,results){
      console.log(err,results);
      return cb(err,results);
    });
  });

但我收到一个错误：

 'E11000 duplicate key error index: xx.$_id_ dup key: { : ObjectId(\'56269dea07a455920a21bca7\') }',

除了我觉得有更好的方法来做到这一点之外

Answer 1

您可能想尝试一种条件类型的更新操作，首先使用带有回调的 .update() 方法根据给定条件更新文档，然后在回调中执行其他更新对于不满足给定标准的文档。例如，您可以将其重组为：

var Model = mongoose.model('myCollection', mySchema);
Model.update(
    {
        "_id": params.documentId,
        "user": params.user,
        "photos.mainPhoto": true            
    }, 
    {
        "$set": {
            "photos.$.mainPhoto": false
        }
    },        
    function(err, numAffected) {        
        Model.update(
            {
                "_id": params.documentId,
                "user": params.user,
                "photos._id": params.photoId /* criteria for setting the updating the documents to true */
            }, 
            {
                "$set": {
                    "photos.$.mainPhoto": true
                }
            },
            function(err, numAffected) {
                /* Update complete. */
            }
        )
    }
)