NoSQL Queries

This pages illustrates details associated with Create, Update and Delete unstructured databases.

//creates a db called saidb or switches to saidb
use saidb

//to view current database
db

//to drop database
db.dropDatabase

//display list of collection
show collections

//Create
db.createCollection('user')

//insert onerror
db.user.insertOne( { name: 'Raghav Mittal'} );

//insert
db.user.insert({
'name': 'Sai Anirudh Karre',
'branch': 'M.Tech CSE',
'joining_year':'2022'
})

//insert many
db.user.insertMany(
[{
'name': 'Sai Anirudh Karre',
'branch': 'M.Tech CSE',
'joining_year':'2022',
'city':'Hyderabad'
},

{'name': 'Chetan Sharma',
'branch': 'M.Tech CASE',
'joining_year':'2021',
'city':'Chennai'
},

{'name': 'Sachin Tendulkar',
'branch': 'M.Tech ECE',
'joining_year':'2021',
'city':'New Delhi'
}])


//search in collection
db.user.find()

//search in collection 
db.user.find({joining_year:'2021'})

//Multivalue Search
db.user.find( { joining_year: { $in: [ "2021", "2022" ] } } )

//expression search
db.user.find( { name: "Chetan Sharma", "joining_year": { $gte: 2021 } } )

//either or 
db.user.find( {
     name: 'Sachin Tendulkar',
     $or: [ { "joining_year": { $gte: 2021 } }, { city: "Hyderabad" } ]
} )


//limit number of rows in collection search
db.user.find().limit(3)

//count number of rows in collection
db.user.find().count()

//update a rows
db.user.updateOne({name: 'Sai Anirudh'},
{$set: {'name': 'Charu Sharma',
    'lang': 'SHELL',
    'Instrutor_since': 2021
}}, {upsert: true})

//update increment operator
db.user.update({name: 'Sachin Tendulkar'},
{$inc:{
    joining_year: 1
}})

//rename column name in Collection
db.user.update({name: 'Sachin Tendulkar'},
{$rename:{
    joining_date: 'year'
}})

//updatemany
db.user.updateMany(
  { year: { $lt: 2022 } },
  {
    $set: { city: 'Hyderabad', branch: 'M.Tech EEE' }
  }
)

//remove row in collection
db.user.remove({name:'Chetan Sharma'})

//regular expression
db.user.find({joining_date: {$lt: 2019}})
db.user.find({joining_date: {$lte: 2019}})
db.user.find({joining_date: {$gt: 2019}})
db.user.find({joining_date: {$gte: 2019}})

//delete all records in collection
db.user.deleteMany({})
db.movies.deleteMany( { name: "Sachin Tendulkar" } )
db.movies.deleteOne( { name: "Lalit Mohan" } )

//delete collection
db.user.drop()