sebprunier/mongodb-aggregation-in-action

MongoDb Aggregation Framework In Action !

MongoDb Aggregation Framework In Action !

How to import datasets?

This is very simple! All you have to do is tu run the script run-all-importers.sh

Marvel dataset online importer

By default, the script run-all-importers.sh uses data available in the data folder. If you have a Marvel account and want to get some fresh data, run the script marvel-comics-importer from the src/importers directory :

MARVEL_PUBLIC_KEY=<your_marvel_public key> MARVEL_PRIVATE_KEY=<your_marvel_private_key> node marvel-comics-importer.js

For more details, see developer.marvel.com

Campings dataset

Group by ranking

Query:

db.campings.aggregate([
    {$group : {_id : "$ranking", total : {$sum : 1}}}
])

Results:

{ "_id" : "5 étoiles", "total" : 177 }
{ "_id" : "4 étoiles", "total" : 940 }
{ "_id" : "3 étoiles", "total" : 2224 }
{ "_id" : "2 étoiles", "total" : 1681 }
{ "_id" : "1 étoile", "total" : 389 }

Top 5 cities with the highest number of campings

Query:

db.campings.aggregate([
    {$group : {_id : "$city", total : {$sum : 1}}},
    {$sort : {total : -1}},
    {$limit : 5},
    {$project: {_id: 0, city : "$_id", total: 1}}
])

Results:

{ "_id" : "ARGELÈS-SUR-MER", "total" : 29 }
{ "_id" : "AGDE", "total" : 23 }
{ "_id" : "VIAS", "total" : 20 }
{ "_id" : "SAINT-JEAN-DE-MONTS", "total" : 20 }
{ "_id" : "LES MATHES", "total" : 17 }

Number of cities with only one camping

Query:

db.campings.aggregate([
    {$group : {_id : "$city", total : {$sum : 1}}},
    {$match : {total : 1}},
    {$group: {_id: null, count: {$sum: 1 }}},
    {$project: {_id: 0, count: 1}}
])

Results:

{ "count" : 2802 }

Marvel Comics dataset

Top 5 characters with the highest number of comics

Query:

db.comics.aggregate([
    {$match : {"characters.returned" : {$gt : 0}}},
    {$project : {title : 1, characters : 1}},
    {$unwind : "$characters.items"},
    {$group : {_id : "$characters.items.name", total : {$sum : 1}}},
    {$sort : {total : -1}},
    {$limit : 5}
])

Results:

{"_id": "Spider-Man","total": 2413}
{"_id": "X-Men","total": 2320}
{"_id": "Iron Man","total": 1904}
{"_id": "Wolverine","total": 1594}
{"_id": "Captain America","total": 1367}

Create the characters collection from the comics collection

Query:

db.comics.aggregate([
    {$match : {"characters.returned" : {$gt : 0}}},
    {$project : {title : 1, characters : 1}},
    {$unwind : "$characters.items"},
    {$group : {_id : "$characters.items.name", total : {$sum : 1}, comics : {$push : {id : "$_id", title : "$title"}}}},
    {$out : "characters"}
])

Results (findOne() query from the characters collection):

{
  "_id": "Frog-Man",
  "total": 2,
  "comics": [
    {
      "id": 38126,
      "title": "Spider-Man: New York Stories (Trade Paperback)"
    },
    {
      "id": 39753,
      "title": "Spider-Island: Avengers (2011) #1"
    }
  ]
}