MongoDB將子文檔的元素移動到另一個子文檔

Question

我需要更改架構

const dataSchema = new Schema({
  trackingPrice: [{
    timeCheck: { type: Date, default: Date.now },
    lowestPrice: Number,
    salePrice: Number,
    saleRank: Number
  }]
})

對此

const dataSchema = new Schema({
  trackingPrice: [{
    timeCheck: { type: Date, default: Date.now },
    lowestPrice: Number,
    salePrice: Number
  }],
  trackingRank: [{
    timeCheck: { type: Date, default: Date.now },
    saleRank: Number
  }]
})

如何在文檔下將數據從一個轉移到另一個，然后刪除“ saleRank”？

Answer 1

我認為最好的方法是找到所有這些，然后每一個創建一個新的

我順便用貓鼬

    dataSchema.find({}, (err,all) => {
          var array = [];
          all.foreach( (ds) => {
            array.push({
              trackingPrice: ds.trackingPrice,
              trackingRank: //whatever way you want to update the old data
           })
           dataSchema.remove({}).exec(() => {
             array.foreach((a) => {
               var toadd = new dataSchema({
                   trackingPrice:a.trackingPrice,
                   trackingRank:a.trackingRank});
               toadd.save();                     
             })             
          })
       })}
    ); 

Answer 2

基於這個很好的答案 ，您的情況下的游標將來自運行聚合管道：

const pipeline = [
    {
        "$project": {
            "trackingPrice": {
                "$map": {
                    "input": "$trackingPrice",
                    "as": "el",
                    "in": { 
                        "timeCheck": "$$el.timeCheck",
                        "lowestPrice": "$$el.timeCheck",
                        "salePrice": "$$el.salePrice"
                    }
                }
            },
            "trackingRank": {
                "$map": {
                    "input": "$trackingPrice",
                    "as": "el",
                    "in": { 
                        "timeCheck": "$$el.timeCheck",
                        "saleRank": "$$el.saleRank"
                    }
                }
            }
        }
    }
];

const cursor = Data.aggregate(pipeline).exec();

運行批量更新：

let bulkUpdateOps = [];

cursor.then(results => {
    results.forEach(doc => {
        const { _id, trackingPrice, trackingRank } = doc;
        bulkUpdateOps.push({
            "updateOne": {
               "filter": { _id },
               "update": { "$set": { trackingPrice, trackingRank } },
               "upsert": true
            }
        });
    }); 

    if (bulkUpdateOps.length === 1000) {
        bulkUpdateOps = [];
        return Data.bulkWrite(bulkUpdateOps);           
    }       

}).then(console.log).catch(console.error);

if (bulkUpdateOps.length > 0) {
    Data.bulkWrite(bulkUpdateOps).then(console.log).catch(console.error);
}