mongo-shell

I have got a collection aTable with 2 records: { "title" : "record 1", "fields" : [ { "_id" : 1, "items" : [ 1 ] }, { "_id" : 2, "items" : [ 2,3,4 ] }, { "_id" : 3, "items" : [ 5 ] } ] }, { "title" : "record 2", "fields" : [ { "_id" : 4, "items" : [ 7,8,9,10 ] }, { "_id" : 5, "items" : [ ] }, { "_id" : 6, "items" : [ 11,12 ] } ] } I want to update fields aTable.fields.items from items : [ 11,12 ] to items : [ {item: 11, key: 0}, {item:12, key: 0} ] I browse fields with forEach but I can't save it: var t = db.aTable.find(); t.forEach(function( aRow ) { aRow.fields.forEach( function( aField ){

If I'm writing an application which connects to mongodb then I can provide a seed list for a replicaset, and the driver will direct me to the master node, where I can run write commands. How do I specify the seed list for a commandline mongo shell in order to conenct to a replicaset. Gianfranco P. To connect to a replica set Primary use the mongo shell --host option: mongo --host replicaSetName/host1[:porthost1],host2[:porthost1],host3[:porthost3],etc For example: $ mongo --host rs1/john.local:27019,john.local:27018 MongoDB shell version: v3.4.9 connecting to: mongodb://john.local:27019,john

2 days old with Mongo and I have a SQL background so bear with me. As with mysql, it is very convenient to be in the MySQL command line and output the results of a query to a file on the machine. I am trying to understand how I can do the same with Mongo, while being in the shell I can easily get the output of a query I want by being outside of the shell and executing the following command: mongo localhost:27017/dbname --eval "printjson(db.collectionName.findOne())" >> sample.json The above way is fine, but it requires me to exit the mongo shell or open a new terminal tab to execute this

MongoDB Aggregation Framework doesn't have floor function. It only has simple arithmetic operators . So, how to compose floor function using them? According to definition floor(number) = number - (number % step) we can compose our aggregation formula: {$subtract: ["$number", {$mod: ["$number", <step>]}]} where step is order of magnitude. First, it computes remainder with $mod and then it computes difference with $subtract . So, grouping Users by age floored to whole numbers will be db.users.aggregate( {$group: {_id: {$subtract: ["$age", {$mod: ["$age", 1]}] }}} ) If you want to floor to 10s or

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. ( note: this is answer to original version of the question, which did not have requirements for "default" ) You can ask it to be pretty. db.collection.find().pretty() staackuser2 You can add DBQuery.prototype._prettyShell = true to your file in $HOME/.mongorc.js to enable pretty print globally by default. Bhanu Chawla (note: this is answer to the updated question) You can just do this on the CLI: echo DBQuery.prototype.

First of, I'm quite new to mongodb. Here's my question I've not been able to find a solution to. Let's say I have 3 different collections. mongos> show collections collectionA collectionB collectionC I want to create a script that iterates over all collections ind this database and find the last inserted timestamp in each of these collections. Here's what works inside mongos. var last_element = db.collectionA.find().sort({_id:-1}).limit(1); printjson(last_element.next()._id.getTimestamp()); ISODate("2014-08-28T06:45:47Z") 1. Problem (Iterate over all collections) Is there any possibility to to