MongoDB Cheat Sheet

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db.coll.insertOne({name: "Max"})
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db.coll.insert([{name: "Max"}, {name:"Alex"}]) // ordered bulk insert
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db.coll.insert([{name: "Max"}, {name:"Alex"}], {ordered: false}) // unordered bulk insert
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db.coll.insert({date: ISODate()})
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db.coll.insert({name: "Max"}, {"writeConcern": {"w": "majority", "wtimeout": 5000}})

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db.coll.findOne() // returns a single document
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db.coll.find()    // returns a cursor - show 20 results - "it" to display more
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db.coll.find().pretty()
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db.coll.find({name: "Max", age: 32}) // implicit logical "AND".
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db.coll.find({date: ISODate("2020-09-25T13:57:17.180Z")})
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db.coll.find({name: "Max", age: 32}).explain("executionStats") // or "queryPlanner" or "allPlansExecution"
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db.coll.distinct("name")
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// Count
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db.coll.count({age: 32})          // estimation based on collection metadata
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db.coll.estimatedDocumentCount()  // estimation based on collection metadata
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db.coll.countDocuments({age: 32}) // alias for an aggregation pipeline - accurate count
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// Comparison
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db.coll.find({"year": {$gt: 1970}})
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db.coll.find({"year": {$gte: 1970}})
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db.coll.find({"year": {$lt: 1970}})
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db.coll.find({"year": {$lte: 1970}})
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db.coll.find({"year": {$ne: 1970}})
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db.coll.find({"year": {$in: [1958, 1959]}})
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db.coll.find({"year": {$nin: [1958, 1959]}})
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// Logical
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db.coll.find({name:{$not: {$eq: "Max"}}})
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db.coll.find({$or: [{"year" : 1958}, {"year" : 1959}]})
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db.coll.find({$nor: [{price: 1.99}, {sale: true}]})
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db.coll.find({
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  $and: [
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    {$or: [{qty: {$lt :10}}, {qty :{$gt: 50}}]},
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    {$or: [{sale: true}, {price: {$lt: 5 }}]}
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  ]
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})
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// Element
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db.coll.find({name: {$exists: true}})
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db.coll.find({"zipCode": {$type: 2 }})
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db.coll.find({"zipCode": {$type: "string"}})
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// Aggregation Pipeline
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db.coll.aggregate([
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  {$match: {status: "A"}},
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  {$group: {_id: "$cust_id", total: {$sum: "$amount"}}},
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  {$sort: {total: -1}}
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])
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// Text search with a "text" index
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db.coll.find({$text: {$search: "cake"}}, {score: {$meta: "textScore"}}).sort({score: {$meta: "textScore"}})
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// Regex
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db.coll.find({name: /^Max/})   // regex: starts by letter "M"
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db.coll.find({name: /^Max$/i}) // regex case insensitive
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// Array
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db.coll.find({tags: {$all: ["Realm", "Charts"]}})
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db.coll.find({field: {$size: 2}}) // impossible to index - prefer storing the size of the array & update it
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db.coll.find({results: {$elemMatch: {product: "xyz", score: {$gte: 8}}}})
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// Projections
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db.coll.find({"x": 1}, {"actors": 1})               // actors + _id
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db.coll.find({"x": 1}, {"actors": 1, "_id": 0})     // actors
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db.coll.find({"x": 1}, {"actors": 0, "summary": 0}) // all but "actors" and "summary"
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// Sort, skip, limit
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db.coll.find({}).sort({"year": 1, "rating": -1}).skip(10).limit(3)
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// Read Concern
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db.coll.find().readConcern("majority")

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db.coll.update({"_id": 1}, {"year": 2016}) // WARNING! Replaces the entire document
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db.coll.update({"_id": 1}, {$set: {"year": 2016, name: "Max"}})
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db.coll.update({"_id": 1}, {$unset: {"year": 1}})
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db.coll.update({"_id": 1}, {$rename: {"year": "date"} })
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db.coll.update({"_id": 1}, {$inc: {"year": 5}})
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db.coll.update({"_id": 1}, {$mul: {price: NumberDecimal("1.25"), qty: 2}})
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db.coll.update({"_id": 1}, {$min: {"imdb": 5}})
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db.coll.update({"_id": 1}, {$max: {"imdb": 8}})
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db.coll.update({"_id": 1}, {$currentDate: {"lastModified": true}})
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db.coll.update({"_id": 1}, {$currentDate: {"lastModified": {$type: "timestamp"}}})
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// Array
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db.coll.update({"_id": 1}, {$push :{"array": 1}})
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db.coll.update({"_id": 1}, {$pull :{"array": 1}})
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db.coll.update({"_id": 1}, {$addToSet :{"array": 2}})
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db.coll.update({"_id": 1}, {$pop: {"array": 1}})  // last element
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db.coll.update({"_id": 1}, {$pop: {"array": -1}}) // first element
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db.coll.update({"_id": 1}, {$pullAll: {"array" :[3, 4, 5]}})
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db.coll.update({"_id": 1}, {$push: {scores: {$each: [90, 92, 85]}}})
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db.coll.updateOne({"_id": 1, "grades": 80}, {$set: {"grades.$": 82}})
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db.coll.updateMany({}, {$inc: {"grades.$[]": 10}})
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db.coll.update({}, {$set: {"grades.$[element]": 100}}, {multi: true, arrayFilters: [{"element": {$gte: 100}}]})
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// Update many
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db.coll.update({"year": 1999}, {$set: {"decade": "90's"}}, {"multi":true})
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db.coll.updateMany({"year": 1999}, {$set: {"decade": "90's"}})
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// FindOneAndUpdate
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db.coll.findOneAndUpdate({"name": "Max"}, {$inc: {"points": 5}}, {returnNewDocument: true})
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// Upsert
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db.coll.update({"_id": 1}, {$set: {item: "apple"}, $setOnInsert: {defaultQty: 100}}, {upsert: true})
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// Replace
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db.coll.replaceOne({"name": "Max"}, {"firstname": "Maxime", "surname": "Beugnet"})
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// Save
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db.coll.save({"item": "book", "qty": 40})
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// Write concern
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db.coll.update({}, {$set: {"x": 1}}, {"writeConcern": {"w": "majority", "wtimeout": 5000}})

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db.coll.remove({name: "Max"})
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db.coll.remove({name: "Max"}, {justOne: true})
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db.coll.remove({}) // WARNING! Deletes all the docs but not the collection itself and its index definitions
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db.coll.remove({name: "Max"}, {"writeConcern": {"w": "majority", "wtimeout": 5000}})
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db.coll.findOneAndDelete({"name": "Max"})