mongo_queries.txt

mongodump -h ds133348.mlab.com:33348/heroku_x4cvh20w  -u login -p pass -o d:\ --gzip

db.createCollection("authors");
db.createCollection("tags");
db.createCollection("articles");

db.authors.findOneAndDelete({"name": /^Mikita.*/})

db.articles.insertMany([
  {
    "title": "Title 1",
    "created_at": new Date(),
    "updated_at": new Date(),
    "author": "supernickname1",
    "tags": [2],
    "likes": 0,
    "article": "it's reaaly big text 1",
    "comments": [
      {
        "first_name": "John",
        "last_name": "Round",
        "message": "very cool"
      }
    ]
  },
  {
    "title": "Title 2",
    "created_at": new Date("2016-12-06"),
    "updated_at": new Date("2016-12-06"),
    "author": "supernickname2",
    "tags": [1, 2, 3],
    "likes": 145,
    "article": "it's reaaly big text 2",
    "comments": [
      {
        "first_name": "Bon",
        "last_name": "Senior",
        "message": "very very cool"
      },
      {
        "first_name": "Bonana",
        "last_name": "Mamba",
        "message": "mmm, tasty!"
      }
    ]
  },
  {
    "title": "Title 3",
    "created_at": new Date("2016-02-15"),
    "updated_at": new Date("2016-09-28"),
    "author": "supernickname3",
    "tags": [2],
    "likes": 1568,
    "article": "it's reaaly big text 3",
    "comments": [
      {
        "first_name": "Jonatan",
        "last_name": "Bound",
        "message": "very cool, very"
      },
      {
        "first_name": "Mark",
        "last_name": "Bounce",
        "message": "very very"
      },
      {
        "first_name": "Yuri",
        "last_name": "Haharin",
        "message": "Let's go"
      }
    ]
  }
])

db.tags.insertMany([
  {
    "_id": 1,
    "name": "tag 1"
  },
  {
    "_id": 2,
    "name": "tag 2"
  },
  {
    "_id": 3,
    "name": "tag 3"
  }
])

db.articles.aggregate([
   {
      $unwind: "$tags"
   }
])

db.articles.aggregate([
   {
      $unwind: "$tags"
   },
   {
      $lookup:
         {
            from: "tags",
            localField: "tags",
            foreignField: "_id",
            as: "tag_descriptions"
        }
   },
   {
      $match: {tag_descriptions: {$elemMatch: {name: "tag 3"}}}
   }
])

db.articles.deleteMany({likes: {$lt: 100}});



db.articles.createIndex({likes: 1});
db.tags.createIndex({name: "text"});


mongoimport -h ds133348.mlab.com:33348/heroku_x4cvh20w -c grades -u login -p pass --file grades.json

db.grades.aggregate([
    {$unwind: "$scores"},
    {$match: {"scores.type": {$ne: "quiz"}}},
    {$group: {
        _id: {
            student_id: "$student_id",
            class_id: "$class_id"
        },
        student_avg: {$avg: "$scores.score"}
    }},
    {$group: {
        _id: "$_id.class_id", 
        class_avg: {$avg: "$student_avg"}
    }},
    {$sort: {"class_avg": -1}},
    {$limit: 1}
])