#MongoDB Cheat Sheet

First steps in the MongoDB World? This cheat sheet is filled with some handy tips, commands, and quick references to get you connected and CRUD'ing in no time!

##Table of Contents

• Connect Via Mongosh
• Helpers
  • Show Databases
  • Switch Database
  • Show Collections
• Database and Collections
  • Drop
  • Run Javascript File
• CRUD
  • Create / Insert
  • Read / View
  • Update
  • Delete/Remove
• MongoDB Operators
  • Query and Projection Operators
  • Update Operations Operator

Connect Via Mongosh

mongosh # connects to mongodb://127.0.0.1:27017 by default
mongosh --host <host> --port <port> --authenticationDatabase admin -u <user> -p <pwd> # omit the password if you want a prompt
mongosh "mongodb://<user>:<password>@192.168.1.1:27017"
mongosh "mongodb://192.168.1.1:27017"
mongosh "mongodb+srv://cluster-name.abcde.mongodb.net/<dbname>" --apiVersion 1 --username <username> # MongoDB Atlas

Helpers

Show Databases

show dbs
db // prints the current database

Switch Database

 use <databaseName> //use mydb

Show Collections

show collections

Database and Collections

Drop

db.<collectionName>.drop() // drop the collection
db.dropDatabase()   // drop the database

Run Javascript File

load("myScript.js")

CRUD

Create / Insert

db.<collectionName>.insertOne()
//Insert one object data into the collection

db.<collectionName>.insertMany()
 //Insert many objects data into the collection as Array of objects

db.<collectionName>.insertMany([{name:"devripon"},{name: "Alex"},{ordered : false}])
 //Insert many objects data into the collection as Array of objects with Unordered

db.<collectionName>.insertOne({date : ISODate()})
 //insert ISO date into the collection

Read / View

    db.<collectionName>.find();
     //Find all objects. it will return 20 data in a page

    db.<collectionName>.findOne();
     //return a single object in the collection

    db.<collectionName>.find().pretty();
     // return all objects in the collection as Prettier formate

    db.<collectionName>.find({name: "devripon",age:30})
     // It will return data logically in the collection by using Implicit Logical `&&` operator

    db.<collectionName>.find({name: "devripon"})
    // search data in the collection by using Object Query

    db.<collectionName>.find({date:ISODate("2023-10-04T07:11:34.113Z")
     // return data by using date query

    db.<collectionName>.distinct("name")
    // it will return all values of name key in the collection

    db.<collectionName>.find({name: "Max", age: 32}).explain("executionStats")
    // it will return data with all execution stats in details


    //Count the number of data in the collection

    db.<collectionName>.countDocuments()
    // it will return the number of documents available in the collection

    db.<collectionName>.estimatedDocuments()
     // it will return the number of documents available in the collection

    db.<collectionName>.countDocuments({name: "devripon"})
    // it will return the number of documents available in the collection of specific object queries


    // find data by comparison

    db.<collectionName>.find({"year":{$gt: 1990}})
    //it return all the data which year value is GRATER THAN 1990

    db.<collectionName>.find({"year":{$gte: 1990}})
    // it return all the data which year value is GRATER THAN and EQUAL of 1990

    db.<collectionName>.find({"year":{$lt: 1990}})
    // it return all the data which year value is LESS THAN 1990

    db.<collectionName>.find({"year":{$lte: 1990}})
    // it return all the data which year value is LESS THAN and EQUAL of 1990

    db.<collectionName>.find({"year":{$ne: 1990}})
     // it return all the data which year value is NOT EQUAL of 1990

    db.<collectionName>.find({"year":{$in:[1990,1995]}})
     //it will return all the data which year value is EITHER 1990 or 1995

    db.<collectionName>.find({"year":{$nin:[1990,1995]}})
     // it will return all the data which year value is NOT 1990 OR 1995

    //Data find logically

    db.<collectionName>.find({name:{$not:{$eq: "devripon"}}})
     // it will return all the data which name value is not equal to "devripon"

    db.<collectionName>.find({$or:[{year:{$lt: 1999}},{year: {$gt: 1970}}]})
     // it will return all the data by matching anyone of those two statements

    db.<collectionName>.find({$nor:[{year:1995},{year:1990}]})
     // it will return all the data which will not match both those two statements

    db.<collectionName>.find({$and:[{year:1995},{year:1987}]})
     // it will return all the data which will match both those two statements

Update

Delete/Remove

MongoDB Operators

Query and Projection Operators

Oerators	Full Meaning
Comparison Operator	This operators are used to compare of different BSON type values
$eq	Matches values that are equal to a specified value.
$gt	Matches values that are greater than a specified value
$gte	Matches values that are greater than or equal to a specified value
$lt	Matches values that are less than a specified value
$lte	Matches values that are less than or equal to a specified value
$ne	Matches values that are not equal to a specified value
$in	Matches any of the values specified in an array.
$nin	Matches none any of the values specified in an array.
Logical Operator	This operators are used for Logical operation in between different BSON type values
$and	Joins query statements with a logical AND && returns all documents that match the conditions of both clauses.
$or	Joins query statements with a logical OR || returns all documents that match the conditions of either clause.
$not	Inverts the effect same as logical ! NOT of a query expression and returns documents that do not match the query expression.
$nor	Joins query statements with a logical NOR that returns all documents that fail to match both statements.
Element Operator	This operators are used for find or check different BSON type values
$exists	Matches documents that have the specified field.
$type	Selects documents if a field is of the specified type.
Evaluation Operator	This operators are used for evaluate in different BSON type data
$expr	Allows use of aggregation expressions within the query language.
$jsonSchema	Allows to Validate documents against the given JSON Schema.
$mod	Performs a modulo operation on the value of a field and selects documents with a specified result.
$regex	Selects documents where values match a specified regular expression.
$text	Performs text search.
$where	Matches documents that satisfy a JavaScript expression.
Array Operator	This operators are used for evaluate in different BSON type data
$all	Matches arrays that contain all elements specified in the query.
$elemMatch	Selects documents if element in the array field matches all the specified $elemMatch conditions
$size	Selects documents if the array field is a specified size.
Projection Operator	This operators are used for projection in different BSON type data
$	Projects the first element in an array that matches the query condition.
$meta	Projects the document's score assigned during $text operation.
$slice	Limits the number of elements projected from an array. Supports skip and limit slices.
Miscellaneous Operator	This operators are used for evaluate in different BSON type data
$comment	Adds a comment to a query predicate.
$rand	Generates a random floating point numbers between 0 and 1.

Update Operations Operator

Fields Update Operator	This operators are used for update Fields
$correntDate	Sets the value of a field to current date, either as a Date or a Timestamp.
$inc	Increments the value of the field by the specified amount.
$min	Only updates the field if the specified value is less than the existing field value.
$max	Only updates the field if the specified value is greater than the existing field value
$mul	Multiplies thevalue of the field by the specified amount.
$rename	Renames a field
$set	Sets the value of a field in a document.
$setOnInsert	Sets the value of a field if an update results in an insert of a document. Has no effect on update operations that modify existing documents.
$unset	Removes the specified field from a document.
Array Update Operator	This operators are used for update Array data
$	Acts as a placeholder to update the first element that matches the query condition.
$[]	Acts as a placeholder to update all elements in an array for the documents that match the query condition.
$[<identifier>]	Acts as a placeholder to update all elements that match the arrayFilters condition for the documents that match the query condition.
$addToSet	Adds elements to an array only if they do not already exist in the set.
$pop	Removes the first or last item of an array.
$pull	Removes all array elements that match a specified query.
$push	Adds an item to an array
$pullAll	Removes all matching values from an array.
$each	Modifies the $push and $addToSet operators to append multiple items for array updates.
$position	Modifies the $push operator to specify the position in the array to add elements.
$slice	Modifies the $push operator to limit the size of updated arrays.
$sort	Modifies the $push operator to reorder documents stored in an array.