Home » Javascript » Can I query MongoDB ObjectId by date?

Can I query MongoDB ObjectId by date?

Posted by: admin November 27, 2017 Leave a comment

Questions:

I know that ObjectIds contain the date they were created on. Is there a way to query this aspect of the ObjectId?

Answers:

Popping Timestamps into ObjectIds covers queries based on dates embedded in the ObjectId in great detail.

Briefly in JavaScript code:

// This function returns an ObjectId embedded with a given datetime
// Accepts both Date object and string input

function objectIdWithTimestamp(timestamp) {
    // Convert string date to Date object (otherwise assume timestamp is a date)
    if (typeof(timestamp) == 'string') {
        timestamp = new Date(timestamp);
    }

    // Convert date object to hex seconds since Unix epoch
    var hexSeconds = Math.floor(timestamp/1000).toString(16);

    // Create an ObjectId with that hex timestamp
    var constructedObjectId = ObjectId(hexSeconds + "0000000000000000");

    return constructedObjectId
}


// Find all documents created after midnight on May 25th, 1980
db.mycollection.find({ _id: { $gt: objectIdWithTimestamp('1980/05/25') } });

Questions:
Answers:

In pymongo, it can be done this way:

import datetime
from bson.objectid import ObjectId
mins = 15
gen_time = datetime.datetime.today() - datetime.timedelta(mins=mins) 
dummy_id = ObjectId.from_datetime(gen_time)
result = list(db.coll.find({"_id": {"$gte": dummy_id}}))

Questions:
Answers:

Using inbuilt function provided by mongodb drivers in in Node.js lets you query by any timestamp:

var timestamp = Date.now();
var objectId = ObjectID.createFromTime(timestamp / 1000);

Alternatively, to search for records before the current time, you can simply do:

var objectId = new ObjectID(); // or ObjectId in the mongo shell

Source: http://mongodb.github.io/node-mongodb-native/api-bson-generated/objectid.html

Questions:
Answers:

Since the first 4 bytes of an ObjectId represent a timestamp, to query your collection chronologically, simply order by id:

# oldest first; use pymongo.DESCENDING for most recent first
items = db.your_collection.find().sort("_id", pymongo.ASCENDING)

After you get the documents, you can get the ObjectId’s generation time like so:

id = some_object_id
generation_time = id.generation_time

Questions:
Answers:

how to find Find the Command (this date[2015-1-12] to this Date[2015-1-15]):

db.collection.find({_id:{$gt: ObjectId(Math.floor((new Date(‘2015/1/12’))/1000).toString(16) + “0000000000000000”), $lt: ObjectId(Math.floor((new Date(‘2015/1/15’))/1000).toString(16) + “0000000000000000”)}}).pretty()

Count the Command (this date[2015-1-12] to this Date[2015-1-15]):

db.collection.count({_id:{$gt: ObjectId(Math.floor((new Date(‘2015/1/12’))/1000).toString(16) + “0000000000000000”), $lt: ObjectId(Math.floor((new Date(‘2015/1/15’))/1000).toString(16) + “0000000000000000”)}})

Remove the Command (this date[2015-1-12] to this Date[2015-1-15]):

db.collection.remove({_id:{$gt: ObjectId(Math.floor((new Date(‘2015/1/12’))/1000).toString(16) + “0000000000000000”), $lt: ObjectId(Math.floor((new Date(‘2015/1/15’))/1000).toString(16) + “0000000000000000”)}})

Questions:
Answers:

To get last 60 days old documents in mongo collection i used below query in shell.

db.collection.find({_id: {$lt:new ObjectId( Math.floor(new Date(new Date()-1000*60*60*24*60).getTime()/1000).toString(16) + "0000000000000000" )}})

Questions:
Answers:

If you want to make a range query, you can do it like in this post. For example querying for a specific day (i.e. Apr 4th 2015):

> var objIdMin = ObjectId(Math.floor((new Date('2015/4/4'))/1000).toString(16) + "0000000000000000")
> var objIdMax = ObjectId(Math.floor((new Date('2015/4/5'))/1000).toString(16) + "0000000000000000")
> db.collection.find({_id:{$gt: objIdMin, $lt: objIdMax}}).pretty()

Questions:
Answers:

From the documentation:

o = new ObjectId()
date = o.getTimestamp()

this way you have date that is a ISODate.

Look at
http://www.mongodb.org/display/DOCS/Optimizing+Object+IDs#OptimizingObjectIDs-Extractinsertiontimesfromidratherthanhavingaseparatetimestampfield.
for more information

Questions:
Answers:

Using MongoObjectID you should also find results as given below

db.mycollection.find({ _id: { $gt: ObjectId("5217a543dd99a6d9e0f74702").getTimestamp().getTime()}});

Leave a Reply

Your email address will not be published. Required fields are marked *