$ addToSet一个对象到mongoose中的数组

Question

我有一个存储少量产品文档的集合.在文档中,有一个数组evaluation用于存储用户对产品的价格评估对象.

以下是用户对象的示例:

var data = {user_id:90,price:400}

任何人都可以告诉我是否有可能在evaluation阵列上执行"插入重复更新" ？我试过了$addToSet,但是当一个对象被推入时evaluation,有一个_id属性被添加到用户对象,即使我在模型中没有它,如下所示:

{
  "_id": 54b13f52604fc5d242d4aa68,
  "__v": NumberInt(0),
  "evaluation": [
    {
      "price": NumberInt(14616),
      "user_id": NumberInt(91),
      "_id": ObjectId("54b13f5e604fc5d242d4aa6b") // Why is it added?
    },
    {
      "price": NumberInt(16211),
      "user_id": NumberInt(92),
      "_id": ObjectId("54b140d1604fc5d242d4aa74") //
    }
  ],
  "product": [
   {
      "title": "ABC",
      "model_id": "382",
      "id": "513",
      "category": "1",
      "src": "xxx.jpg"
    }
  ],
  "timestamp":ISODate("2015-01-10T15:03:46.310Z")
}

那是如何$addToSet使用id字段来检查重复的对象？

model.js

var evaluation = new mongoose.Schema({
       product:[],
       timestamp : { type : Date, default: Date.now },
       evaluation:[{user_id:Number,price:Number}],
},{strict:false});

var models = {
      Eva:mongoose.model('Evaluation',evaluation)
    };

app.js

var mongo_models = require('./db/mongo_model')(mongoose);
Eva = mongo_models.Eva;

io.on('connection', function(socket){
  socket.on("evaluation",function(d){
    var data = {user_id:user_id,price:d.price};
    Eva.update({_id:d.tid},{$addToSet:{evaluation:data}}).exec();
  })
})

Answer 1

您可以通过为元素声明内联架构并禁用来防止 Mongoose 向数组元素添加_id字段：evaluation_id

var evaluation = new mongoose.Schema({
   product:[],
   timestamp : { type : Date, default: Date.now },
   evaluation:[Schema({user_id:Number,price:Number}, {_id: false})],
},{strict:false});