MongoDB集合上的Mongoose模型不提取数据

我正在使用MongoDB 3.4.7版本，Mongoose 4.11.13驱动程序在MongoDB集合上创build模型，并创buildAggregationCursor来单独处理每个文档以填充一些JSvariables。 但似乎Mongoose模型没有将任何数据从MongoDB集合中带入游标。 我以前用mongodb驱动尝试过集合操作，但是不起作用（在这里检查） ，而是select了mongoose 。 但是这里似乎还有一些问题，或者我在这里丢失了什么？ 为了更好的理解，更新了我的AggregationCursor。 任何快速的帮助将不胜感激。

节点版本3.10.10，ExpressJS 3.2.6

我的Node.JS代码如下：

 app.get('/reviews',function(req,res) { res.render("chart"); var obj = {}; var mongoose = require('mongoose'); var assert = require('assert'); var schema = new mongoose.Schema({ seller_id: String, product_id: String, product_desc: String, reviews: { total_review_count: Number, five_star_count: Number, four_star_count: Number, three_star_count: Number, two_star_count: Number, one_star_count: Number } }); //specify the name of MongoDB collection as third argument of model var ProductReview = mongoose.model('ProductReview', schema, 'product_reviews'); //<-- here //review count placeholders var totalReviewCounts = [], FiveStarCounts = [], FourStarCounts = [], ThreeStarCounts = [], TwoStarCounts = [], OneStarCounts = []; mongoose.connect('mongodb://localhost:27017/sellerrank', function() { var cursor = ProductReview.aggregate([ { $match: { seller_id: { $exists: true, $nin: [null] } } } ]) .allowDiskUse(true) .group({ _id: { seller_id: '$seller_id'}, total_review_count: { $sum: { $cond : [ { $eq : ["$reviews.total_review_count", null] }, 0, "$reviews.total_review_count" ] } }, five_star_count: { $sum: { $cond : [ { $eq : ["$reviews.five_star_count", null] }, 0, "$reviews.five_star_count" ] } }, four_star_count: { $sum: { $cond : [ { $eq : ["$reviews.four_star_count", null] }, 0, "$reviews.four_star_count" ] } }, three_star_count: { $sum: { $cond : [ { $eq : ["$reviews.three_star_count", null] }, 0, "$reviews.three_star_count" ] } }, two_star_count: { $sum: { $cond : [ { $eq : ["$reviews.two_star_count", null] }, 0, "$reviews.two_star_count" ] } }, one_star_count: { $sum: { $cond : [ { $eq : ["$reviews.one_star_count", null] }, 0, "$reviews.one_star_count" ] } } }) .cursor({ batchSize: 100}) .exec(); console.log(cursor); **//<-- printing the cursor here** cursor.each(function(err,doc){ assert.equal(null,err); console.log(doc); if(doc!=null){ var seller_id = doc['_id']; var totalReviews = doc['total_review_count']; var fiveStarReviews = doc['five_star_count']; var fourStarReviews = doc['four_star_count']; var threeStarReviews = doc['three_star_count']; var twoStarReviews = doc['two_star_count']; var oneStarReviews = doc['one_star_count']; totalReviewCounts.push({"value" : totalReviews}); FiveStarCounts.push({"value" : fiveStarReviews}); FourStarCounts.push({"value" : fourStarReviews}); ThreeStarCounts.push({"value" : threeStarReviews}); TwoStarCounts.push({"value" : twoStarReviews}); OneStarCounts.push({"value" : oneStarReviews}); } }); }); var dataset = [ { "seriesname" : "Total positive reviews", "data" : totalReviewCounts }, { "seriesname" : "5 star reviews", "data": FiveStarCounts }, { "seriesname" : "4 star reviews", "data" : FourStarCounts }, { "seriesname" : "3 star reviews", "data": ThreeStarCounts }, { "seriesname" : "2 star reviews", "data" : TwoStarCounts }, { "seriesname" : "1 star reviews", "data": OneStarCounts } ]; console.log(dataset); //<-- **dataset is printed here** var response = { "dataset" : dataset }; obj['dataset'] = dataset; console.log(obj); res.send(obj); mongoose.disconnect(); }); 

当我运行上面的Node.JS Express代码时，我得到了console.log(dataset)的输出

 [ { seriesname: 'Total positive reviews', data: [] }, { seriesname: '5 star reviews', data: [] }, { seriesname: '4 star reviews', data: [] }, { seriesname: '3 star reviews', data: [] }, { seriesname: '2 star reviews', data: [] }, { seriesname: '1 star reviews', data: [] } ] 

在我的本地MongoDB集合“product_reviews”中有数据，但没有数据被提取到游标中。

console.log(cursor)显示的我的聚合游标如下所示：

 AggregationCursor { pool: null, server: null, disconnectHandler: Store { s: { storedOps: [], storeOptions: [Object], topology: [Object] }, length: [Getter] }, bson: BSON {}, ns: 'sellerrank.product_reviews', cmd: { aggregate: 'product_reviews', pipeline: [ [Object], [Object] ], allowDiskUse: true, cursor: { batchSize: 100 } }, options: { allowDiskUse: true, cursor: { batchSize: 100 }, promiseLibrary: [Function: Promise], cursorFactory: { [Function: AggregationCursor] super_: [Object], define: [Object], INIT: 0, OPEN: 1, CLOSED: 2 }, disconnectHandler: Store { s: [Object], length: [Getter] } }, topology: Server { domain: null, _events: { reconnect: [Function: reconnectHandler], reconnectFailed: [Function: reconnectFailedHandler], serverDescriptionChanged: [Function], serverHeartbeatStarted: [Function], serverHeartbeatSucceeded: [Function], serverHeartbeatFailed: [Function], serverOpening: [Function], serverClosed: [Function], topologyOpening: [Function], topologyClosed: [Function], topologyDescriptionChanged: [Function], attemptReconnect: [Function], monitoring: [Function], timeout: [Function], error: [Object], close: [Function], destroy: [Function: destroyHandler] }, _eventsCount: 17, _maxListeners: undefined, id: 0, s: { options: [Object], logger: [Object], Cursor: [Object], bson: BSON {}, pool: [Object], disconnectHandler: [Object], monitoring: true, inTopology: false, monitoringInterval: 5000, topologyId: -1, serverDescription: [Object], topologyDescription: [Object] }, ismaster: { ismaster: true, maxBsonObjectSize: 16777216, maxMessageSizeBytes: 48000000, maxWriteBatchSize: 1000, localTime: 2017-10-02T14:21:27.032Z, maxWireVersion: 5, minWireVersion: 0, readOnly: false, ok: 1 }, lastIsMasterMS: 12, monitoringProcessId: Timeout { _called: false, _idleTimeout: 5000, _idlePrev: [Object], _idleNext: [Object], _idleStart: 5621, _onTimeout: [Function], _timerArgs: undefined, _repeat: null }, initalConnect: false, wireProtocolHandler: WireProtocol { legacyWireProtocol: WireProtocol {} }, _type: 'server', clientInfo: { driver: [Object], os: [Object], platform: 'Node.js v6.11.3, LE, mongodb-core: 2.1.15' }, lastUpdateTime: 0, lastWriteDate: 0, staleness: 0 }, cursorState: { cursorId: null, cmd: { aggregate: 'product_reviews', pipeline: [Object], allowDiskUse: true, cursor: [Object] }, documents: [], cursorIndex: 0, dead: false, killed: false, init: false, notified: false, limit: 0, skip: 0, batchSize: 100, currentLimit: 0, transforms: undefined }, logger: Logger { className: 'Cursor' }, _readableState: ReadableState { objectMode: true, highWaterMark: 16, buffer: BufferList { head: null, tail: null, length: 0 }, length: 0, pipes: null, pipesCount: 0, flowing: null, ended: false, endEmitted: false, reading: false, sync: true, needReadable: false, emittedReadable: false, readableListening: false, resumeScheduled: false, defaultEncoding: 'utf8', ranOut: false, awaitDrain: 0, readingMore: false, decoder: null, encoding: null }, readable: true, domain: null, _events: {}, _eventsCount: 0, _maxListeners: undefined, s: { maxTimeMS: null, state: 0, streamOptions: {}, bson: BSON {}, ns: 'sellerrank.product_reviews', cmd: { aggregate: 'product_reviews', pipeline: [Object], allowDiskUse: true, cursor: [Object] }, options: { allowDiskUse: true, cursor: [Object], promiseLibrary: [Function: Promise], cursorFactory: [Object], disconnectHandler: [Object] }, topology: Server { domain: null, _events: [Object], _eventsCount: 17, _maxListeners: undefined, id: 0, s: [Object], ismaster: [Object], lastIsMasterMS: 12, monitoringProcessId: [Object], initalConnect: false, wireProtocolHandler: [Object], _type: 'server', clientInfo: [Object], lastUpdateTime: 0, lastWriteDate: 0, staleness: 0 }, topologyOptions: { host: 'localhost', port: 27017, disconnectHandler: [Object], cursorFactory: [Object], reconnect: true, emitError: true, size: 5, socketOptions: {}, auto_reconnect: true, clientInfo: [Object], forceServerObjectId: false, w: 1, promiseLibrary: [Function: Promise], bson: BSON {} }, promiseLibrary: [Function: Promise] }, sortValue: undefined, eachAsync: [Function] }