Follow

Keep Up to Date with the Most Important News

By pressing the Subscribe button, you confirm that you have read and are agreeing to our Privacy Policy and Terms of Use
Contact

Unable to retrieve multiple values from database

The following data exists in the database:

[
    {
        "_id": {
            "$oid": "628c787de53612aad30021ab"
        },
        "ticker": "EURUSD",
        "dtyyyymmdd": "20030505",
        "time": "030000",
        "open": "1.12161",
        "high": "1.12209",
        "low": "1.12161",
        "close": "1.12209",
        "vol": "561",
        "id": 1
    },
    {
        "_id": {
            "$oid": "628c787de53612aad30021ac"
        },
        "ticker": "EURUSD",
        "dtyyyymmdd": "20030505",
        "time": "030100",
        "open": "1.12206",
        "high": "1.1225",
        "low": "1.12206",
        "close": "1.1225",
        "vol": "1223",
        "id": 2
    },
    {
        "_id": {
            "$oid": "628c787de53612aad30021ad"
        },
        "ticker": "EURUSD",
        "dtyyyymmdd": "20030505",
        "time": "030200",
        "open": "1.12238",
        "high": "1.12247",
        "low": "1.12225",
        "close": "1.12231",
        "vol": "816",
        "id": 3
    }
]

If you pull out a single value, for example, through the command:

.findOne({id: 1});

There are no problems and everything works fine.
The problem occurs when getting multiple values from the base – for example:

MEDevel.com: Open-source for Healthcare and Education

Collecting and validating open-source software for healthcare, education, enterprise, development, medical imaging, medical records, and digital pathology.

Visit Medevel

.find({ticker:"EURUSD"}));

Such a command produces the following output:

FindCursor {
  _events: [Object: null prototype] {},
  _eventsCount: 0,
  _maxListeners: undefined,
  [Symbol(kCapture)]: false,
  [Symbol(topology)]: Topology {
    _events: [Object: null prototype] {
      connectionPoolCreated: [Function (anonymous)],
      connectionPoolClosed: [Function (anonymous)],
      connectionCreated: [Function (anonymous)],
      connectionReady: [Function (anonymous)],
      connectionClosed: [Function (anonymous)],
      connectionCheckOutStarted: [Function (anonymous)],
      connectionCheckOutFailed: [Function (anonymous)],
      connectionCheckedOut: [Function (anonymous)],
      connectionCheckedIn: [Function (anonymous)],
      connectionPoolCleared: [Function (anonymous)],
      commandStarted: [Function (anonymous)],
      commandSucceeded: [Function (anonymous)],
      commandFailed: [Function (anonymous)],
      serverOpening: [Function (anonymous)],
      serverClosed: [Function (anonymous)],
      serverDescriptionChanged: [Function (anonymous)],
      topologyOpening: [Function (anonymous)],
      topologyClosed: [Function (anonymous)],
      topologyDescriptionChanged: [Function (anonymous)],
      error: [Function (anonymous)],
      timeout: [Function (anonymous)],
      close: [Function (anonymous)],
      serverHeartbeatStarted: [Function (anonymous)],
      serverHeartbeatSucceeded: [Function (anonymous)],
      serverHeartbeatFailed: [Function (anonymous)]
    },
    _eventsCount: 25,
    _maxListeners: undefined,
    bson: [Object: null prototype] {
      serialize: [Function: serialize],
      deserialize: [Function: deserialize]
    },
    s: {
      id: 0,
      options: [Object: null prototype],
      seedlist: [Array],
      state: 'connected',
      description: [TopologyDescription],
      serverSelectionTimeoutMS: 30000,
      heartbeatFrequencyMS: 10000,
      minHeartbeatFrequencyMS: 500,
      servers: [Map],
      sessionPool: [ServerSessionPool],
      sessions: Set(0) {},
      credentials: undefined,
      clusterTime: undefined,
      connectionTimers: Set(0) {},
      detectShardedTopology: [Function: detectShardedTopology],
      detectSrvRecords: [Function: detectSrvRecords]
    },
    [Symbol(kCapture)]: false,
    [Symbol(waitQueue)]: Denque {
      _head: 2,
      _tail: 2,
      _capacity: undefined,
      _capacityMask: 3,
      _list: [Array]
    }
  },
  [Symbol(namespace)]: MongoDBNamespace { db: 'Trading', collection: 'EUR/USD' },
  [Symbol(documents)]: [],
  [Symbol(initialized)]: false,
  [Symbol(closed)]: false,
  [Symbol(killed)]: false,
  [Symbol(options)]: {
    readPreference: ReadPreference {
      mode: 'primary',
      tags: undefined,
      hedge: undefined,
      maxStalenessSeconds: undefined,
      minWireVersion: undefined
    },
    fieldsAsRaw: {},
    promoteValues: true,
    promoteBuffers: false,
    promoteLongs: true,
    serializeFunctions: false,
    ignoreUndefined: false,
    bsonRegExp: false,
    raw: false,
    enableUtf8Validation: true
  },
  [Symbol(filter)]: { ticker: 'EURUSD' },
  [Symbol(builtOptions)]: {
    raw: false,
    promoteLongs: true,
    promoteValues: true,
    promoteBuffers: false,
    ignoreUndefined: false,
    bsonRegExp: false,
    serializeFunctions: false,
    fieldsAsRaw: {},
    enableUtf8Validation: true,
    readPreference: ReadPreference {
      mode: 'primary',
      tags: undefined,
      hedge: undefined,
      maxStalenessSeconds: undefined,
      minWireVersion: undefined
    }
  }
}

Question:
Why is this happening and how to get the needed result?

>Solution :

find return value is a cursor in nodejs, there are several ways on how you can use it to access the data, you can read about them here

The easiest way is to use the .toArray() cursor function which just converts the cursor to an array of documents, like so:

const results = await db.collection.find({ticker:"EURUSD"})).toArray();
Add a comment

Leave a Reply

Keep Up to Date with the Most Important News

By pressing the Subscribe button, you confirm that you have read and are agreeing to our Privacy Policy and Terms of Use

Discover more from Dev solutions

Subscribe now to keep reading and get access to the full archive.

Continue reading