MongoDB

July 16, 2022 . Developer Environment
  • MongoDB is a document database designed for ease of development and scaling.
  • It is intuitive and easy to use NoSQL Database.
  • Available as community and enterprise edition.

“mongo” is the command line shell that connects to a specific instance of mongod

“mongod” is the “Mongo Daemon” it’s basically the host process for the database.

MongoDB internally uses BSON, because BSON is very efficient compared to JSON. In MongoDB instead of tables like SQL it has collections, and rows are known as documents.

In MongoDB the key: value pair of each document is called field: value

Install: for personal use you going to install MongoDB Community Version with Community server. While installing always make sure to have checkbox option is clicked for run mongod as a service

Always make sure to add the path if working on the Windows Machine.

Go to directory where MongoDB is installed = MongoDB->Server->4.4(Version)->bin-> add to path. To run the executables of the MongoDB.

MongoDB Compass

Most Common Commands for MongoDB

Database Command
  1. View all databases

    show dbs

  2. Create a new or switch databses

    use dbName

  3. View current database

    db

  4. Delete databse

    db.dropDatabase()

Collection Commands
  1. Show Collections

    show collections

  2. Create a collection named “name”

    db.createCollection(‘name’)

  3. Drop a collection named “name”

    db.name.drop()

Row(Document) Commands
  1. Show all rows in a collection

    db.name.find()

  2. Show all rows in a collection(prettified)

    db.name.find().pretty()

  3. Find the first row matching the object

    db.name.findOne({name: ‘Shubham’})

  4. Insert one row

    db.name.insert({ ‘name’: ‘Shubham’, ‘lang’: ‘Python’, ‘member’: ‘Student })

  5. Insert many rows

    db.name.insertMany([{ ‘name’: ‘Shubham’, ‘lang’: ‘Python’, ‘member’: ‘Student }, { ‘name’: ‘Shubh’, ‘lang’: ‘C++’, ‘member’: ‘Student }, { ‘name’: ‘Shubhammm’, ‘lang’: ‘Java’, ‘member’: ‘Student }])

  6. Search in MongoDB Database

    db.name.find({‘lang’: ‘Java’})

  7. Limit the number of rows in output

    db.name.find().limit(2)

  8. Count the number of rows in the output

    db.name.find().count()

  9. Update a row

    db.name.update({name: ‘Shivam’}, {‘name’: ‘Shubham’, ‘lang’: ‘Python’, ‘member’: ‘Student }, {upsert: true})

  10. Mongodb Increment Operator

    db.name.update({name: ‘Shubham’}, { $inc:{ member: 22 } })

  11. Rename Operator

    db.name.update({name:’Shubham’}, {$rename:{ member: ‘mem’ }})

  12. Delete row

    db.name.remove({name: ‘Shubham})

  13. Less than/Greater than/ Less than or Equal/Greater than or Equal

    db.name.find({member: {$lt: 90}}) db.name.find({member: {$lte: 90}}) db.name.find({member: {$gt: 90}}) db.name.find({member: {$gte: 90}})