MongoProject

# config

//cmd1

mongod --configsvr --port 27020 --dbpath C:\Users\wbazela\Desktop\Mongodb_p\config --replSet confSet

//cmd2

mongo --port 27020

rs.initiate({_id:"confSet", configsvr:true, members:[{_id:0, host:"127.0.0.1:27020"}]})
use ourProjectBase

# shard 1

//cmd3

mongod --shardsvr --replSet shard1Set --dbpath C:\Users\wbazela\Desktop\Mongodb_p\sh11 --port 27021

//cmd4

mongod --port 27022 --dbpath C:\Users\wbazela\Desktop\Mongodb_p\sh12 --replSet shard1Set

# shard 2

//cmd5

mongod --shardsvr --replSet shard2Set --dbpath C:\Users\wbazela\Desktop\Mongodb_p\sh21 --port 27023

//cmd6

mongod --port 27024 --dbpath C:\Users\wbazela\Desktop\Mongodb_p\sh22 --replSet shard2Set

# sharding

//cmd7

mongo --port 27021
rs.initiate({_id:"shard1Set", members:[{_id:0, host:"127.0.0.1:27021"}]})
rs.add("127.0.0.1:27022")
use ourProjectBase

//cmd8

mongo --port 27023
rs.initiate({_id:"shard2Set", members:[{_id:0, host:"127.0.0.1:27023"}]})
rs.add("127.0.0.1:27024")
use ourProjectBase

# finale

//cmd9

mongos --configdb confSet/127.0.0.1:27020

//cmd10

mongo

sh.addShard("shard1Set/127.0.0.1:27021")
sh.addShard("shard2Set/127.0.0.1:27023")
sh.enableSharding("ourProjectBase")
use ourProjectBase

sh.shardCollection("ourProjectBase.Students",{album_nr:"hashed"})

db.Students.insertMany([
    {
        'album_nr': 110120,
        'year_of_study': 3,
        'year_in_dormitories': 2,
        'major': 'Data Engineering',
		'lives_in': 'DS6',
        'function': {
            'function_name': 'gym_master',
            'dorm_id': 'DS6',
            'points_granted': 13
        }
    },
    {
        'album_nr': 110130,
        'year_of_study': 5,
        'year_in_dormitories': 1,
        'major': 'Data Science',
		'lives_in': 'DS6',
        'function': {
            'function_name': 'laundry_room_keeper',
            'dorm_id': 'DS6',
            'points_granted': 7
        }
    },
    {
        'album_nr': 110140,
        'year_of_study': 1,
        'year_in_dormitories': 1,
        'major': 'Chemistry',
	'lives_in': 'DS7',
    }
])
db.Dormitories.insertMany([
    {
        'dorm_id': 'DS6',
	'address': 'Gdansk ul. Pana Golaszewskiego 15',
        'rooms': [
            {
                'room_id': 100,
                'room_capacity': 2
            },
            {
                'room_id': 101,
                'room_capacity': 3
            },
            {
                'room_id': 102,
                'room_capacity': 2
            },
            {
                'room_id': 200,
                'room_capacity': 2
            },
            {
                'room_id': 201,
                'room_capacity': 3
            },
            {
                'room_id': 202,
                'room_capacity': 3
            }
        ]

    },

    {
        'dorm_id': 'DS7',
	'address': 'Gdansk ul. Pana Golaszewskiego 14',
        'rooms': [
            {
                'room_id': 100,
                'room_capacity': 3
            },
            {
                'room_id': 101,
                'room_capacity': 2
            },
            {
                'room_id': 102,
                'room_capacity': 4
            }
        ]
    }
])

1.

db.Dormitories.aggregate([
    { '$unwind': '$rooms' },
    { '$match': {} },
    { '$group': { '_id': "$dorm_id", 'how_many_people_can_live': { '$sum': "$rooms.room_capacity" } } }
])

2.

db.Students.find({$or:[{'major': /.*Data.*/}, {'major': /.*data.*/}]})

3.

db.Students.aggregate([
   {
      $lookup:
         {
            from: "Dormitories",
            localField: "lives_in",
            foreignField: "dorm_id",
            as: "Dorm_info"
        }
   },
   { '$unwind': '$Dorm_info' },
   {'$project': {'Dorm_info.address':1, 'Students.album_nr':1}}
])

4.

db.Students.find({$and:[{'year_in_dormitories': {$gt: 1}}, {'year_of_study': {$gt: 1}}]})

5.

db.Students.find({$or:[{function:null},{function:{$size:0}}]})