猫鼬查询两个集合抛出错误

Question

router.get('/programs/:url', (req, res) => {
    var url = req.params.url;
    var query = {}
    query['url']=url;
    query['active'] = true;
    ProgramModel.aggregate([
    { $match: query },
    {  $lookup: { from: "episode", // collection name in db
                  localField: "_id",
                  foreignField: "show_id",
                  as: "episode"
                  }
    },
    { $sort: { _id: -1 } }]).exec(function(err, programs) {
    if (!err){ 
            res.status(200).json({
            programs
            })
            //process.exit();
        } else {throw err;}
    // students contain WorksnapsTimeEntries
});

//    res.status(200).json({
//       message: "You're authorized to see to edit pages.",
       // user values passed through from auth middleware
       //user: req.user
//     });

   });

我在让ProgramModel加入我的节目集和剧集集合时遇到问题。

基本上我需要先打电话给show collection

http://www.example.com/api/programs/showname

我得到的错误是

/root/react-passport-example/node_modules/mongodb/lib/utils.js:123
    process.nextTick(function() { throw err; });
                                  ^
MongoError: The 'cursor' option is required, except for aggregate with the explain argument
    at Function.MongoError.create (/root/react-passport-example/node_modules/mongodb-core/lib/error.js:31:11)
    at /root/react-passport-example/node_modules/mongodb-core/lib/connection/pool.js:497:72
    at authenticateStragglers (/root/react-passport-example/node_modules/mongodb-core/lib/connection/pool.js:443:16)        at Connection.messageHandler (/root/react-passport-example/node_modules/mongodb-core/lib/connection/pool.js:477:5)      at Socket.<anonymous> (/root/react-passport-example/node_modules/mongodb-core/lib/connection/connection.js:321:22)      at emitOne (events.js:116:13)
    at Socket.emit (events.js:211:7)
    at addChunk (_stream_readable.js:263:12)
    at readableAddChunk (_stream_readable.js:250:11)
    at Socket.Readable.push (_stream_readable.js:208:10)
    at TCP.onread (net.js:607:20)

我该如何使用它？我尝试运行的查询如下：

db.getCollection('shows').aggregate([
                     { $match: { _id: ObjectId("5d622cecbbe890f60ccd1ca4") } },
                     {  $lookup: { from: "episode", // collection name in db
                                   localField: "_id",
                                   foreignField: "show_id",
                                   as: "episode"
                                   }
                     },
                     { $sort: { total: -1 } }
                   ])

版本 “猫鼬”：“ ^ 4.10.4”，

MongoDB 4.0.10