mongo.org

Operations

Show Databases

show dbs 

Use a database called test

use test

Insert data into a collection products

db.products.insert(
{ "description": "motorcycle",
  "price"      : 1000 })

Finding

To find all items in a collection

db.products.find()

Find substring

db.products.find({description: /c/i })
db.products.find({description: 'motorcycle' })

MongoDB Client

Give us the model name

$group {
   _id: "$model"

Create a property maxValue in the returned object:

$group {
   maxValue:

Set it’s value to the the maximum of the memory column:

{$max: "$memory"}

function aggProds(){
    MongoClient.connect("mongodb://localhost:27017/meanpcdb", function(err, db) {
        if(err) { return console.dir(err); }
        var cursor = db.collection('products').aggregate([{
            $group: {
                _id:"$model",
                "maxValue": {$max:"$memory"}}}]);

        cursor.get(function(err, results) {
            console.log(results);
        });
        return null;
    });
}

gives:

[ { _id: 'iPhone 6 Plus', maxValue: 128 } ]
nn#+END_SRC

from data:

[{"category":"thumb drive",
  "capacity":32,
  "price":50,
  "currency":"CAD",
  "brand":"Kingston",
  "model":"DataTraveler 101 G2",
  "usb2":"true"
 },
 {"category": "phone",
  "price":749,
  "model":"iPhone 6 Plus",
  "memory":16},
{"category": "phone",
  "price":849,
  "model":"iPhone 6 Plus",
  "memory":64},
{"category": "phone",
  "price":949,
  "model":"iPhone 6 Plus",
  "memory":128}]