MongoDB Commands Cheat Sheet

Basic Commands

# Start MongoDB server
mongod

# Connect to MongoDB
mongo

Database Commands

# Show all databases
show dbs

# Switch to a database (or create it if it doesn't exist)
use database_name

# Get the current database
db

# Drop the current database
db.dropDatabase()

Collection Commands

# Show all collections in the current database
show collections

# Create a collection
db.createCollection("collection_name")

# Drop a collection
db.collection_name.drop()

Document Commands

# Insert a document into a collection
db.collection_name.insert({key1: "value1", key2: "value2"})

# Insert multiple documents into a collection
db.collection_name.insertMany([{key1: "value1"}, {key2: "value2"}])

# Find the first document that matches a query
db.collection_name.findOne({key: "value"})

# Find all documents in a collection
db.collection_name.find()

# Find documents that match a query
db.collection_name.find({key: "value"})

# Find documents with specific fields
db.collection_name.find({key: "value"}, {field1: 1, field2: 1})

# Update a document
db.collection_name.updateOne({key: "value"}, {$set: {field: "new_value"}})

# Update multiple documents
db.collection_name.updateMany({key: "value"}, {$set: {field: "new_value"}})

# Replace a document
db.collection_name.replaceOne({key: "value"}, {new_key: "new_value"})

# Delete a document
db.collection_name.deleteOne({key: "value"})

# Delete multiple documents
db.collection_name.deleteMany({key: "value"})

Query Operators

# Greater than
db.collection_name.find({key: {$gt: value}})

# Less than
db.collection_name.find({key: {$lt: value}})

# Greater than or equal to
db.collection_name.find({key: {$gte: value}})

# Less than or equal to
db.collection_name.find({key: {$lte: value}})

# Not equal to
db.collection_name.find({key: {$ne: value}})

# In
db.collection_name.find({key: {$in: [value1, value2]}})

# Not in
db.collection_name.find({key: {$nin: [value1, value2]}})

Index Commands

# Create an index
db.collection_name.createIndex({key: 1})

# Create a unique index
db.collection_name.createIndex({key: 1}, {unique: true})

# Drop an index
db.collection_name.dropIndex("index_name")

# Get all indexes
db.collection_name.getIndexes()

Aggregation Commands

# Count the number of documents in a collection
db.collection_name.countDocuments()

# Group documents by a key and perform an aggregation
db.collection_name.aggregate([
  {$group: {_id: "$key", total: {$sum: "$field"}}}
])

# Match documents in an aggregation pipeline
db.collection_name.aggregate([
  {$match: {key: "value"}}
])

# Project specific fields in an aggregation pipeline
db.collection_name.aggregate([
  {$project: {field1: 1, field2: 1}}
])

Other Useful Commands

# Get information about the current connection
db.stats()

# Get information about a collection
db.collection_name.stats()

# Get the current operation
db.currentOp()

# Kill an operation
db.killOp(opid)

# Run a command
db.runCommand({command: 1})

# List all users
db.getUsers()

# Create a user
db.createUser({
  user: "username",
  pwd: "password",
  roles: [{role: "readWrite", db: "database_name"}]
})

# Drop a user
db.dropUser("username")