mongoDB_Sheet.txt

MongoDb commands for Databases
View all databases
show dbs

create a new or switch databases
use dbName

View current databases
db

Delete Database
db.dropDatabase()

MongoDb commands for Collections
show Collections
show collections


Create a collections named 'comments'
db.createCollection('comments')
db.createCollection('suman') // another example

Delete a collections named 'suman'
db.<collection name>.drop()
db.suman.drop() //example


MongoDb commands for Rows
Show all Rows in a collection
db.comments.find() // collection name = 'comments' 
db.suman.find() // collection name  = 'suman'

Find the first row matching the object
db.comments.findOne({'name':'suman'})


Show all Rows in a Collections (Prettified)
 db.comments.find().pretty()


Insert One/Single Rows (collection name = 'comments')
db.comments.insert({
  'name':'suman',
  'lang':'JavaScript',
  'member_since':5
})

Insert Multiple Rows
db.comments.insertMany([
  {
  'name':'suman',
  'lang':'JavaScript',
  'member_since':5
},
  {
  'name':'aman',
  'lang':'Python',
  'member_since':6
},  {
  'name':'ram',
  'lang':'Java',
  'member_since':15
}, ])

Show Rows by specific key in a collection
db.comments.find({'name':'ram'}) // ram wala row aayega
db.comments.find({'lang':'Java'}) // java wala row ...


 
 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()
db.comments.find({'name':'suman'}).count()

Find by sorted order (increasing order)
db.comments.find().sort({member_since:1}).pretty()

Find by sorted order (Decreasing order)
db.comments.find().sort({member_since: -1}).pretty()


Update a row
db.comments.update({name:'suman'},
 {
  'name':'suman',
  'lang':'JavaScript/ typeScript',
  'member_since':50
}, {upsert: true} )


Mongodb Increment Operator
db.comments.update({name:'suman'},{
$inc:{
  member_since:2
}})

Mongodb Rename Operator
db.comments.update({name:'suman'},{
$inc:{
  member_since:'member'
}})

Delete Row
db.comments.remove({name:'suman'})