Questions tagged [mongodb]

MongoDB is a scalable, cross-platform, high-performance, open source, document-oriented NoSQL database. It supports a large number of languages and application development platforms. Questions about server administration can be asked on https://dba.stackexchange.com

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47 answers
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How to query MongoDB with "like"

I want to query something with SQL's like query: SELECT * FROM users WHERE name LIKE '%m%' How can I achieve the same in MongoDB? I can't find an operator for like in the documentation.
Freewind's user avatar
  • 196k
1183 votes
16 answers
353k views

"Large data" workflows using pandas [closed]

I have tried to puzzle out an answer to this question for many months while learning pandas. I use SAS for my day-to-day work and it is great for it's out-of-core support. However, SAS is horrible ...
Zelazny7's user avatar
  • 40.4k
971 votes
16 answers
775k views

Query for documents where array size is greater than 1

I have a MongoDB collection with documents in the following format: { "_id" : ObjectId("4e8ae86d08101908e1000001"), "name" : ["Name"], "zipcode" : ["2223"] } { "_id" : ObjectId("...
emson's user avatar
  • 10.3k
935 votes
22 answers
518k views

How do I drop a MongoDB database from the command line?

What's the easiest way to do this from my bash prompt?
coffee-grinder's user avatar
910 votes
23 answers
1.0m views

How can I list all collections in the MongoDB shell?

In the MongoDB shell, how do I list all collections for the current database that I'm using?
coffee-grinder's user avatar
774 votes
13 answers
679k views

Find MongoDB records where array field is not empty

All of my records have a field called "pictures". This field is an array of strings. I now want the newest 10 records where this array IS NOT empty. I've googled around, but strangely enough I haven'...
Jelle De Loecker's user avatar
764 votes
6 answers
316k views

MongoDB vs. Cassandra [closed]

I am evaluating what might be the best migration option. Currently, I am on a sharded MySQL (horizontal partition), with most of my data stored in JSON blobs. I do not have any complex SQL queries (...
meow's user avatar
  • 27.8k
746 votes
17 answers
896k views

Checking if a field contains a string

I'm looking for an operator, which allows me to check, if the value of a field contains a certain string. Something like: db.users.findOne({$contains:{"username":"son"}}) Is that possible?
johnny's user avatar
  • 8,936
716 votes
14 answers
836k views

Find document with array that contains a specific value

If I have this schema... person = { name : String, favoriteFoods : Array } ... where the favoriteFoods array is populated with strings. How can I find all persons that have "sushi" as their ...
Ludwig Magnusson's user avatar
692 votes
7 answers
209k views

When to use CouchDB over MongoDB and vice versa

I am stuck between these two NoSQL databases. In my project, I will be creating a database within a database. For example, I need a solution to create dynamic tables. So users can create tables with ...
Luke101's user avatar
  • 64.3k
691 votes
16 answers
762k views

How to get the last N records in mongodb?

I can't find anywhere it has been documented this. By default, the find() operation will get the records from beginning. How can I get the last N records in mongodb? Edit: also I want the returned ...
Bin Chen's user avatar
  • 62.5k
684 votes
11 answers
896k views

How do you query for "is not null" in Mongo?

I would like to execute a following query: db.mycollection.find(HAS IMAGE URL) What should be the correct syntax?
TIMEX's user avatar
  • 266k
640 votes
19 answers
571k views

How do I perform the SQL Join equivalent in MongoDB?

How do I perform the SQL Join equivalent in MongoDB? For example say you have two collections (users and comments) and I want to pull all the comments with pid=444 along with the user info for each. ...
The Unknown's user avatar
  • 19.5k
635 votes
10 answers
244k views

MongoDB relationships: embed or reference?

I want to design a question structure with some comments. Which relationship should I use for comments: embed or reference? A question with some comments, like stackoverflow, would have a structure ...
Freewind's user avatar
  • 196k
595 votes
12 answers
297k views

How do you rename a MongoDB database?

There's a typo in my MongoDB database name and I'm looking to rename the database. I can copy and delete like so... db.copyDatabase('old_name', 'new_name'); use old_name db.dropDatabase(); Is there ...
Brian Hempel's user avatar
  • 8,964
574 votes
8 answers
168k views

Pretty print in MongoDB shell as default

Is there a way to tell Mongo to pretty print output? Currently, everything is output to a single line and it's difficult to read, especially with nested arrays and documents.
raffian's user avatar
  • 31.7k
558 votes
17 answers
1.1m views

Find objects between two dates MongoDB

I've been playing around storing tweets inside mongodb, each object looks like this: { "_id" : ObjectId("4c02c58de500fe1be1000005"), "contributors" : null, "text" : "Hello world", "user" : { "...
Tom's user avatar
  • 34k
548 votes
28 answers
488k views

Mongod complains that there is no /data/db folder

I am using my new mac for the first time today. I am following the get started guide on the mongodb.org up until the step where one creates the /data/db directory. btw, I used the homebrew route. So ...
Nik So's user avatar
  • 16.8k
544 votes
12 answers
392k views

Update MongoDB field using value of another field

In MongoDB, is it possible to update the value of a field using the value from another field? The equivalent SQL would be something like: UPDATE Person SET Name = FirstName + ' ' + LastName And the ...
Chris Fulstow's user avatar
538 votes
17 answers
383k views

Delete everything in a MongoDB database

I'm doing development on MongoDB. For totally non-evil purposes, I sometimes want to blow away everything in a database—that is, to delete every single collection, and whatever else might be lying ...
Trevor Burnham's user avatar
531 votes
10 answers
127k views

When to use MongoDB or other document oriented database systems? [closed]

We offer a platform for video- and audio-clips, photos and vector-grafics. We started with MySQL as the database backend and recently included MongoDB for storing all meta-information of the files, ...
aurora's user avatar
  • 9,607
509 votes
23 answers
714k views

How do I update/upsert a document in Mongoose?

Perhaps it's the time, perhaps it's me drowning in sparse documentation and not being able to wrap my head around the concept of updating in Mongoose :) Here's the deal: I have a contact schema and ...
Traveling Tech Guy's user avatar
494 votes
22 answers
517k views

How to execute mongo commands through shell scripts?

I want to execute mongo commands in shell script, e.g. in a script test.sh: #!/bin/sh mongo myDbName db.mycollection.findOne() show collections When I execute this script via ./test.sh, then the ...
StackOverFlow's user avatar
485 votes
20 answers
489k views

Retrieve only the queried element in an object array in MongoDB collection

Suppose you have the following documents in my collection: { "_id":ObjectId("562e7c594c12942f08fe4192"), "shapes":[ { "shape":"square", "color":"blue" }, ...
Sebtm's user avatar
  • 7,112
485 votes
19 answers
132k views

MongoDB or CouchDB - fit for production? [closed]

I was wondering if anyone can tell me if MongoDB or CouchDB are ready for a production environment. I'm now looking at these storage solutions (I'm favouring MongoDB at the moment), however these ...
477 votes
18 answers
473k views

How to remove a field completely from a MongoDB document?

{ name: 'book', tags: { words: ['abc','123'], lat: 33, long: 22 } } Suppose this is a document. How do I remove "words" completely from all the documents in this ...
TIMEX's user avatar
  • 266k
473 votes
8 answers
571k views

Add new field to every document in a MongoDB collection

How can I add a new field to every document in an existent collection? I know how to update an existing document's field but not how to add a new field to every document in a collection. How can I do ...
Filippo oretti's user avatar
467 votes
34 answers
497k views

How to export all collections in MongoDB?

I want to export all collections in MongoDB by the command: mongoexport -d dbname -o Mongo.json The result is: No collection specified! The manual says, if you don't specify a collection, all ...
aboutstudy's user avatar
  • 4,977
466 votes
10 answers
331k views

When to Redis? When to MongoDB? [closed]

What I want is not a comparison between Redis and MongoDB. I know they are different; the performance and the API is totally different. Redis is very fast, but the API is very 'atomic'. MongoDB will ...
445 votes
30 answers
227k views

How can I get a random record from MongoDB?

I am looking to get a random record from a huge collection (100 million records). What is the fastest and most efficient way to do so? The data is already there and there are no field in which I can ...
Will M's user avatar
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444 votes
20 answers
633k views

How to secure MongoDB with username and password

I want to set up user name & password authentication for my MongoDB instance, so that any remote access will ask for the user name & password. I tried the tutorial from the MongoDB site and ...
murvinlai's user avatar
  • 49.7k
436 votes
9 answers
253k views

What is the "__v" field in Mongoose

I'm using Mongoose version 3 with MongoDB version 2.2. I've noticed a __v field has started appearing in my MongoDB documents. Is it something to do with versioning? How is it used?
Simon Lomax's user avatar
  • 8,862
431 votes
17 answers
464k views

Mongoose: findOneAndUpdate doesn't return updated document

Below is my code var mongoose = require('mongoose'); mongoose.connect('mongodb://localhost/test'); var Cat = mongoose.model('Cat', { name: String, age: {type: Number, default: 20}, ...
Dreams's user avatar
  • 8,438
406 votes
13 answers
733k views

How do I search for an object by its ObjectId in the mongo console?

I've found this question answered for C# and Perl, but not in the native interface. I thought this would work: db.theColl.find( { _id: ObjectId("4ecbe7f9e8c1c9092c000027") } ) The query returned no ...
jcollum's user avatar
  • 45.1k
400 votes
27 answers
460k views

MongoDB: Is it possible to make a case-insensitive query?

Example: > db.stuff.save({"foo":"bar"}); > db.stuff.find({"foo":"bar"}).count(); 1 > db.stuff.find({"foo":"BAR"}).count(); 0
Luke Dennis's user avatar
  • 14.4k
397 votes
25 answers
688k views

How to select a single field for all documents in a MongoDB collection?

In my MongoDB, I have a student collection with 10 records having fields name and roll. One record of this collection is: { "_id" : ObjectId("53d9feff55d6b4dd1171dd9e"), "name" : "Swati", ...
Shipra Swati's user avatar
  • 4,169
377 votes
9 answers
388k views

MySQL vs MongoDB 1000 reads

I have been very excited about MongoDb and have been testing it lately. I had a table called posts in MySQL with about 20 million records indexed only on a field called 'id'. I wanted to compare ...
Imran Omar Bukhsh's user avatar
377 votes
25 answers
278k views

Get names of all keys in the collection

I'd like to get the names of all the keys in a MongoDB collection. For example, from this: db.things.insert( { type : ['dog', 'cat'] } ); db.things.insert( { egg : ['cat'] } ); db.things.insert( { ...
Steve's user avatar
  • 4,919
367 votes
24 answers
595k views

E11000 duplicate key error index in mongodb mongoose

Following is my user schema in user.js model - var userSchema = new mongoose.Schema({ local: { name: { type: String }, email : { type: String, require: true, unique: true }, ...
Trialcoder's user avatar
  • 5,926
362 votes
13 answers
158k views

How do I manage MongoDB connections in a Node.js web application?

I'm using the node-mongodb-native driver with MongoDB to write a website. I have some questions about how to manage connections: Is it enough using only one MongoDB connection for all requests? Are ...
Freewind's user avatar
  • 196k
361 votes
9 answers
333k views

mongodb/mongoose findMany - find all documents with IDs listed in array

I have an array of _ids and I want to get all docs accordingly, what's the best way to do it ? Something like ... // doesn't work ... of course ... model.find({ '_id' : [ '...
ezmilhouse's user avatar
  • 9,053
349 votes
24 answers
574k views

How do I remove documents using Node.js Mongoose?

FBFriendModel.find({ id: 333 }, function (err, docs) { docs.remove(); //Remove all the documents that match! }); The above doesn't seem to work. The records are still there. Can someone fix?...
TIMEX's user avatar
  • 266k
348 votes
9 answers
510k views

MongoDB SELECT COUNT GROUP BY

I am playing around with MongoDB trying to figure out how to do a simple SELECT province, COUNT(*) FROM contest GROUP BY province But I can't seem to figure it out using the aggregate function. I ...
Steven's user avatar
  • 13.7k
345 votes
8 answers
514k views

How to list all databases in the mongo shell?

I know how to list all collections in a particular database, but how do I list all available databases in MongoDB shell?
fracz's user avatar
  • 21k
340 votes
12 answers
625k views

MongoDB - return query based on date

I have a data like this in mongodb { "latitude" : "", "longitude" : "", "course" : "", "battery" : "0", "imei" : "0", "altitude" : "F:3.82V", "mcc" : "07", "...
coure2011's user avatar
  • 41.3k
337 votes
4 answers
336k views

How to search in array of object in mongodb

Suppose the mongodb document(table) 'users' is { _id: 1, name: { first: 'John', last: 'Backus' }, birth: new Date('Dec 03, 1924'), death: new Date('Mar 17, 2007'), ...
vcxz's user avatar
  • 4,098
337 votes
7 answers
158k views

Ways to implement data versioning in MongoDB

Can you share your thoughts how would you implement data versioning in MongoDB. (I've asked similar question regarding Cassandra. If you have any thoughts which db is better for that please share) ...
Piotr Czapla's user avatar
  • 26.1k
331 votes
8 answers
141k views

Stop Mongoose from creating _id property for sub-document array items

If you have subdocument arrays, Mongoose automatically creates ids for each one. Example: { _id: "mainId" subDocArray: [ { _id: "unwantedId", field: "value" }, ...
Atlas's user avatar
  • 3,413
331 votes
12 answers
493k views

Push items into mongo array via mongoose

Basically I have a mongodb collection called 'people' whose schema is as follows: people: { name: String, friends: [{firstName: String, lastName: String}] } Now, I have a ...
Neurax's user avatar
  • 3,717
329 votes
17 answers
532k views

MongoDB - admin user not authorized

I am trying to add authorization to my MongoDB. I am doing all this on Linux with MongoDB 2.6.1. My mongod.conf file is in the old compatibility format (this is how it came with the installation). ...
peter.petrov's user avatar
  • 38.9k

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