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MongoDB CheatSheet
The most commonly used MongoDB commands are given here.
2022-10-27

Table of Contents

Mongo-DB CheatSheet for Developers

Database Commands

Command Description
createUser Creates a new user.
show dbs View all databases
use dbName Create a new or switch databases
db View current Database
db.dropDatabase() Delete Database
usersInfo Returns information about the specified users.

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Collection Commands

Command Description
db.createCollection('collection_name') Create a collection named 'collection_name'
db.collection_name.drop() Drop a collection named 'collection_name'

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Row(Document) Commands

Command Description
db.collection_name.find() Show all Rows in a Collection
db.collection_name.find().pretty() Show all Rows in a Collection (Prettified)
db.collection_name.findOne({name: 'ritwik'}) Find the first row matching the object
db.collection_name.insert({'name': 'Ritwik','lang': 'sql','member_since': 5 }) Insert One Row
db.collection_name.insertMany([{'name': 'Ritwik','lang': 'sql','member_since': 5}, {'name': 'Rohan','lang': 'Python','member_since': 3},{'name': 'Lovish','lang': 'Java','member_since': 4}]) Insert many Rows
db.collection_name.find({lang:'Python'}) Search in a MongoDb Database
db.collection_name.find().limit(2) Limit the number of rows in output
db.collection_name.find().count() Count the number of rows in the output
db.collection_name.updateOne({name: 'Shubham'},{$set: {'name': 'Harry','lang': 'JavaScript','member_since': 51}},{upsert: true}) Update a row
db.collection_name.update({name: 'Rohan'},{$inc:{member_since: 2}}) Mongodb Increment Operator
db.collection_name.update({name: 'Rohan'},{$rename:{member_since: 'member'}}) Mongodb Rename Operator
db.collection_name.remove({name: 'Harry'}) Delete Row
db.collection_name.deleteOne({name: 'Harry'}) Delete one Row
db.collection_name.deleteMany({lang: 'JavaScript'}) Delete many Row

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MongoDB Query Operators

There are many query operators that can be used to compare and reference document fields.

Comparison Operators

The following operators can be used in queries to compare values:

Command Description
$eq Values are equal
$ne Values are not equal
$gt Value is greater than another value
$gte Value is greater than or equal to another value
$lt Value is less than another value
$lte Value is less than or equal to another value
$in Value is matched within an array

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Logical Operators

The following operators can logically compare multiple queries.

Command Description
$and Returns documents where both queries match
$or Returns documents where either query matches
$nor Returns documents where both queries fail to match
$not Returns documents where the query does not match

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Evaluation Operators

The following operators assist in evaluating documents.

Command Description
$regex Allows the use of regular expressions when evaluating field values
$text Performs a text search
$where Uses a JavaScript expression to match documents

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MongoDB Update Operators

There are many update operators that can be used during document updates.

Fields

The following operators can be used to update fields:

Command Description
$currentDate Sets the field value to the current date
$inc Increments the field value
$rename Renames the field
$set Sets the value of a field
$unset Removes the field from the document

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Array

The following operators assist with updating arrays.

Command Description
$addToSet Adds distinct elements to an array
$pop Removes the first or last element of an array
$pull Removes all elements from an array that match the query
$push Adds an element to an array

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MongoDB - Aggregation

Expression Description
$sum Sums up the defined value from all documents in the collection.
$avg Calculates the average of all given values from all documents in the collection.
$min Gets the minimum of the corresponding values from all documents in the collection.
$max Gets the maximum of the corresponding values from all documents in the collection.
$push Inserts the value to an array in the resulting document.
$addToSet Inserts the value to an array in the resulting document but does not create duplicates.
$first Gets the first document from the source documents according to the grouping. Typically this makes only sense together with some previously applied “$sort”-stage.
$last Gets the last document from the source documents according to the grouping. Typically this makes only sense together with some previously applied “$sort”-stage.

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