MongoDB Cheat Sheet

Show All Databases

show dbs

Displays a list of all available databases.

Show Current Database

db

Shows the name of the current working database.

Create Or Switch Database

use new_database

Creates a new database if it doesn't exist or switches to an existing one.

Drop Database

db.dropDatabase()

Deletes the current database.

Create Collection

db.createCollection('posts')

Creates a new collection named 'posts' in the current database.

Show Collections

show collections

Lists all collections in the current database.

Insert Row

db.posts.insert({
    title: 'Post One',
    body: 'Body of post one',
    category: 'News',
    tags: ['news', 'events'],
    user: {
    name: 'John Doe',
    status: 'author'
},
    date: Date()
})

Inserts a new document (row) into the 'posts' collection.

Insert Multiple Rows

db.posts.insertMany([
    // ... multiple documents
])

Inserts multiple documents into the 'posts' collection.

Get All Rows

db.posts.find()

Retrieves all documents from the 'posts' collection.

Get All Rows Formatted

db.posts.find().pretty()

Formats and displays all documents from the 'posts' collection.

Find Rows

db.posts.find({ category: 'News' })

Retrieves documents from 'posts' where the category is 'News'.

Sort Rows

# Ascending

db.posts.find().sort({ title: 1 }).pretty()

# Descending

db.posts.find().sort({ title: -1 }).pretty()

Sorts documents based on the specified field.

Count Rows

db.posts.find().count()
db.posts.find({ category: 'news' }).count()

Counts the number of documents in the 'posts' collection.

Limit Rows

db.posts.find().limit(2).pretty()

Limits the number of retrieved documents from the 'posts' collection.

Chaining

db.posts.find().limit(2).sort({ title: 1 }).pretty()

Chains multiple operations to refine query results.

Foreach

db.posts.find().forEach(function(doc) {
    print("Blog Post: " + doc.title)
})

Applies a function to each document in the 'posts' collection.

Find One Row

db.posts.findOne({ category: 'News' })

Retrieves the first document that matches the specified query.

Find Specific Fields

db.posts.find({ title: 'Post One' }, {
    title: 1,
    author: 1
})

Retrieves specific fields from documents in the 'posts' collection.

Update Row

db.posts.update({ title: 'Post Two' },
{
    title: 'Post Two',
    body: 'New body for post 2',
    date: Date()
},
{
    upsert: true
})

Updates or inserts a document in the 'posts' collection.

Update Specific Field

db.posts.update({ title: 'Post Two' },
{
    $set: {
        body: 'Body for post 2',
        category: 'Technology'
    }
})

Updates specific fields in a document.

Increment Field ($inc)

db.posts.update({ title: 'Post Two' },
{
$inc: {
    likes: 5
}
})

Increments a numeric field in a document.

Rename Field

db.posts.update({ title: 'Post Two' },
{
$rename: {
    likes: 'views'
}
})

Renames a field in a document.

Delete Row

db.posts.remove({ title: 'Post Four' })

Removes documents from the 'posts' collection based on the specified query.

Sub-Documents

db.posts.update({ title: 'Post One' },
{
    $set: {
    comments: [
    // ... array of comments
    ]
    }
})

Adds sub-documents (comments) to an existing document.

Find By Element in Array ($elemMatch)

db.posts.find({
    comments: {
    $elemMatch: {
        user: 'Mary Williams'
    }
    }
})

Finds documents containing specific elements in an array.

Add Index

db.posts.createIndex({ title: 'text' })

Creates an index on the 'title' field for text search.

Text Search

db.posts.find({
    $text: {
        $search: "\"Post O\""
    }
})

Performs a text search on the 'posts' collection.

Greater & Less Than

db.posts.find({ views: { $gt: 2 } })
db.posts.find({ views: { $gte: 7 } })
db.posts.find({ views: { $lt: 7 } })
db.posts.find({ views: { $lte: 7 } })

Retrieves documents with numeric values greater or less than specified.