MongoDb

 

1. Database Commands

View all databases

show dbs

Create a new or switch databases 

use dbName

View current Database

db

Delete Database 

db.dropDatabase()

2. Collection Commands

Show Collections

show collections

Create a collection named 'comments'

db.createCollection('comments')

Drop a collection named 'comments'

db.comments.drop()

3. Row(Document) Commands

Show all Rows in a Collection 

db.comments.find()

Show all Rows in a Collection (Prettified)

db.comments.find().pretty()

Find the first row matching the object

db.comments.findOne({name: 'Harry'})

Insert One Row

db.comments.insert({
    'name': 'Harry',
    'lang': 'JavaScript',
    'member_since': 5
 })

Insert many Rows

db.comments.insertMany([{
    'name': 'Harry',
    'lang': 'JavaScript',
    'member_since': 5
    }, 
    {'name': 'Rohan',
    'lang': 'Python',
    'member_since': 3
    },
    {'name': 'Lovish',
    'lang': 'Java',
    'member_since': 4
}])

Search in a MongoDb Database

db.comments.find({lang:'Python'})

Limit the number of rows in output

db.comments.find().limit(2)

Count the number of rows in the output

db.comments.find().count()

Update a row

db.comments.updateOne({name: 'Shubham'},
{$set: {'name': 'Harry',
    'lang': 'JavaScript',
    'member_since': 51
}}, {upsert: true})

Mongodb Increment Operator

db.comments.update({name: 'Rohan'},
{$inc:{
    member_since: 2
}})

Mongodb Rename Operator

db.comments.update({name: 'Rohan'},
{$rename:{
    member_since: 'member'
}})

Delete Row 

db.comments.remove({name: 'Harry'})

Less than/Greater than/ Less than or Eq/Greater than or Eq

db.comments.find({member_since: {$lt: 90}})

db.comments.find({member_since: {$lte: 90}})

db.comments.find({member_since: {$gt: 90}})

db.comments.find({member_since: {$gte: 90}})