We inherited a system that uses MongoDB, and I managed to get the sandbox online without actually learning anything about Mongo. The other environments, though, have data people care about set up in a replicated cluster of database servers. That seems like the sort of thing that’s going to require knowing more than “it’s a NoSQL database of some sort”.

It is a NoSQL database — documents are organized into ‘collections’ within the database. You can have multiple databases hosted on a server, too. A document is a group of key/value pairs with dynamic schema (i.e. you can just make up keys as you go).

There are GUI clients and a command-line shell … of course I’m going with the shell 🙂 There is a db function for basic CRUD operations using db.nameOfCollection then the operation type:

db.collectionName.insert({"key1": "string1", "key2" : false, "key3": 12345})

db.collectionName.find({key3 : {$gt : 10000} })

db.collectionName.update({key1 : "string1"}, {$set: {key3: 100}})

db.collectionName.remove({key1: "string1"});

CRUD operations can also be performed with NodeJS code — create a file with the script you want to run, then run “node myfile.js”

Create a document in a collection

var objMongoClient = require('mongodb').MongoClient;
var strMongoDBURI = "mongodb://mongodb.example.com:27017/";
  
objMongoClient.connect(strMongoDBURI, function(err, db) {
  if (err) throw err;
    var dbo = db.db("dbNameToSelect");
    var objRecord = { key1: "String Value1", key2: false };
    dbo.collection("collectionName").insertOne(objRecord, function(err, res) {
         if (err) throw err;
         console.log("document inserted");
         db.close();
    });
}); 

Read a document in a collection

var objMongoClient = require('mongodb').MongoClient;
var strMongoDBURI = "mongodb://mongodb.example.com:27017/";

objMongoClient.connect(strMongoDBURI, function(err, db) {
  if (err) throw err;
    var dbo = db.db("dbNameToSelect");
    var objQuery = { key1: "String Value 1" };
    dbo.collection("collectionName").find(objQuery).toArray(function(err, result) {
     if (err) throw err;
     console.log(result);
     db.close();
  });
}); 

Update a document in a collection

var objMongoClient = require('mongodb').MongoClient;
var strMongoDBURI = "mongodb://mongodb.example.com:27017/";

objMongoClient.connect(strMongoDBURI, function(err, db) {
if (err) throw err;
  var dbo = db.db("dbNameToSelect");
  var objRecord= { key1: "String Value 1" };
  dbo.collection("collectionName").deleteOne(objRecord, function(err, obj) {
    if (err) throw err;
    console.log("Record deleted");
    db.close();
});
}); 

Delete a document in a collection

var objMongoClient = require('mongodb').MongoClient;
var strMongoDBURI = "mongodb://mongodb.example.com:27017/";

objMongoClient.connect(strMongoDBURI, function(err, db) {
if (err) throw err;
  var dbo = db.db("dbNameToSelect");
  var objQuery = { key1: "String Value 1" };
  var objNewValues = { $set: {key3: 12345, key4: "Another string value" } };
  dbo.collection("collectionName").updateOne(objQuery, objNewValues , function(err, res) {
    if (err) throw err;
    console.log("Record updated");
    db.close();
   });
});