Question

      db.getCollection('Leave').find({},{_id:0 , 
      Can_It_Be_carry_forwarded:1})

这在MongoDb客户端CMD中可以正常运行，但在下面的代码中却不能正常运行

      var MongoClient = require('mongodb').MongoClient;
      var url = "mongodb://localhost:27017/Chatbot_Project";

      MongoClient.connect(url, function(err, db) {
         if (err) throw err;

         var dbo = db.db("Chatbot_Project");
         dbo.collection('Leave').find({}, {Can_It_Be_carry_forwarded:1}).toArray(function(err, result) {
            if (err) 
              throw err;

            console.log(result);
            db.close();
         })
       });

Answer 1

您的问题是find方法，您缺少投影字段。如果您只想检索Can_It_Be_carry_forwarded字段，则需要以下内容：{projection:{Can_It_Be_carry_forwarded:1, _id: 0}}作为第二个参数。

类似问题的解决方案：https://stackoverflow.com/a/48294672/4120554

文档：http://mongodb.github.io/node-mongodb-native/3.0/api/Collection.html#find

尝试一下：

  var MongoClient = require('mongodb').MongoClient;
  var url = "mongodb://localhost:27017/Chatbot_Project";

  MongoClient.connect(url, function(err, db) {
     if (err) throw err;

     var dbo = db.db("Chatbot_Project");
     dbo.collection('Leave').find({},{projection:{_id: 0, Can_It_Be_carry_forwarded:1}}).toArray(function(err, result) {
        if (err) 
          throw err;

        console.log(result);
        db.close();
     })
   });

NodeJ和MongoDB

1 个答案: