Getting Started
Connect MongoDB Shell
mongo # connects to mongodb://127.0.0.1:27017 by default
mongo --host <host> --port <port> -u <user> -p <pwd> # omit the password if you want a prompt
mongo "mongodb://192.168.1.1:27017"
mongo "mongodb+srv://cluster-name.abcde.mongodb.net/<dbname>" --username <username> # MongoDB Atlas
Helpers
show dbs :
db // prints the current database
Switch database :
use <database_name>
Show collections :
show collections
Run JavaScript file :
load("myScript.js")
Crud
Create
db.coll.insertOne({name: "Max"})
db.coll.insert([{name: "Max"}, {name:"Alex"}]) // ordered bulk insert
db.coll.insert([{name: "Max"}, {name:"Alex"}], {ordered: false}) // unordered bulk insert
db.coll.insert({date: ISODate()})
db.coll.insert({name: "Max"}, {"writeConcern": {"w": "majority", "wtimeout": 5000}})
Delete
db.coll.remove({name: "Max"})
db.coll.remove({name: "Max"}, {justOne: true})
db.coll.remove({}) // WARNING! Deletes all the docs but not the collection itself and its index definitions
db.coll.remove({name: "Max"}, {"writeConcern": {"w": "majority", "wtimeout": 5000}})
db.coll.findOneAndDelete({"name": "Max"})
Update
db.coll.update({"_id": 1}, {"year": 2016}) // WARNING! Replaces the entire document
db.coll.update({"_id": 1}, {$set: {"year": 2016, name: "Max"}})
db.coll.update({"_id": 1}, {$unset: {"year": 1}})
db.coll.update({"_id": 1}, {$rename: {"year": "date"} })
db.coll.update({"_id": 1}, {$inc: {"year": 5}})
db.coll.update({"_id": 1}, {$mul: {price: NumberDecimal("1.25"), qty: 2}})
db.coll.update({"_id": 1}, {$min: {"imdb": 5}})
db.coll.update({"_id": 1}, {$max: {"imdb": 8}})
db.coll.update({"_id": 1}, {$currentDate: {"lastModified": true}})
db.coll.update({"_id": 1}, {$currentDate: {"lastModified": {$type: "timestamp"}}})
Array
db.coll.update({"_id": 1}, {$push :{"array": 1}})
db.coll.update({"_id": 1}, {$pull :{"array": 1}})
db.coll.update({"_id": 1}, {$addToSet :{"array": 2}})
db.coll.update({"_id": 1}, {$pop: {"array": 1}}) // last element
db.coll.update({"_id": 1}, {$pop: {"array": -1}}) // first element
db.coll.update({"_id": 1}, {$pullAll: {"array" :[3, 4, 5]}})
db.coll.update({"_id": 1}, {$push: {scores: {$each: [90, 92, 85]}}})
db.coll.updateOne({"_id": 1, "grades": 80}, {$set: {"grades.$": 82}})
db.coll.updateMany({}, {$inc: {"grades.$[]": 10}})
db.coll.update({}, {$set: {"grades.$[element]": 100}}, {multi: true, arrayFilters: [{"element": {$gte: 100}}]})
Update many
db.coll.update({"year": 1999}, {$set: {"decade": "90's"}}, {"multi":true})
db.coll.updateMany({"year": 1999}, {$set: {"decade": "90's"}})
FindOneAndUpdate
db.coll.findOneAndUpdate({"name": "Max"}, {$inc: {"points": 5}}, {returnNewDocument: true})
Upsert
db.coll.update({"_id": 1}, {$set: {item: "apple"}, $setOnInsert: {defaultQty: 100}}, {upsert: true})
Replace
db.coll.replaceOne({"name": "Max"}, {"firstname": "Maxime", "surname": "Beugnet"})
Save
db.coll.save({"item": "book", "qty": 40})
Write concern
db.coll.update({}, {$set: {"x": 1}}, {"writeConcern": {"w": "majority", "wtimeout": 5000}})
Find
db.coll.findOne() // returns a single document
db.coll.find() // returns a cursor - show 20 results - "it" to display more
db.coll.find().pretty()
db.coll.find({name: "Max", age: 32}) // implicit logical "AND".
db.coll.find({date: ISODate("2020-09-25T13:57:17.180Z")})
db.coll.find({name: "Max", age: 32}).explain("executionStats") // or "queryPlanner" or "allPlansExecution"
db.coll.distinct("name")
Count
db.coll.count({age: 32}) // estimation based on collection metadata
db.coll.estimatedDocumentCount() // estimation based on collection metadata
db.coll.countDocuments({age: 32}) // alias for an aggregation pipeline - accurate count
Comparison
db.coll.find({"year": {$gt: 1970}})
db.coll.find({"year": {$gte: 1970}})
db.coll.find({"year": {$lt: 1970}})
db.coll.find({"year": {$lte: 1970}})
db.coll.find({"year": {$ne: 1970}})
db.coll.find({"year": {$in: [1958, 1959]}})
db.coll.find({"year": {$nin: [1958, 1959]}})
Logical
db.coll.find({name:{$not: {$eq: "Max"}}})
db.coll.find({$or: [{"year" : 1958}, {"year" : 1959}]})
db.coll.find({$nor: [{price: 1.99}, {sale: true}]})
db.coll.find({
$and: [
{$or: [{qty: {$lt :10}}, {qty :{$gt: 50}}]},
{$or: [{sale: true}, {price: {$lt: 5 }}]}
]
})
Element
db.coll.find({name: {$exists: true}})
db.coll.find({"zipCode": {$type: 2 }})
db.coll.find({"zipCode": {$type: "string"}})
Aggregation Pipeline
db.coll.aggregate([
{$match: {status: "A"}},
{$group: {_id: "$cust_id", total: {$sum: "$amount"}}},
{$sort: {total: -1}}
])
Text search with a “text” index
db.coll.find({$text: {$search: "cake"}}, {score: {$meta: "textScore"}}).sort({score: {$meta: "textScore"}})
Regex
db.coll.find({name: /^Max/}) // regex: starts by letter "M"
db.coll.find({name: /^Max$/i}) // regex case insensitive
Array
db.coll.find({tags: {$all: ["Realm", "Charts"]}})
db.coll.find({field: {$size: 2}}) // impossible to index - prefer storing the size of the array & update it
db.coll.find({results: {$elemMatch: {product: "xyz", score: {$gte: 8}}}})
Projections
db.coll.find({"x": 1}, {"actors": 1}) // actors + \_id
db.coll.find({"x": 1}, {"actors": 1, "\_id": 0}) // actors
db.coll.find({"x": 1}, {"actors": 0, "summary": 0}) // all but "actors" and "summary"
Sort, skip, limit
db.coll.find({}).sort({"year": 1, "rating": -1}).skip(10).limit(3)
Read Concern
db.coll.find().readConcern("majority")
Databases and Collections
Drop
db.coll.drop() // removes the collection and its index definitions
db.dropDatabase() // double check that you are *NOT* on the PROD cluster... :-)
Create Collection
db.createCollection("contacts", {
validator: {$jsonSchema: {
bsonType: "object",
required: ["phone"],
properties: {
phone: {
bsonType: "string",
description: "must be a string and is required"
},
email: {
bsonType: "string",
pattern: "@mongodb\.com$",
description: "must be a string and match the regular expression pattern"
},
status: {
enum: [ "Unknown", "Incomplete" ],
description: "can only be one of the enum values"
}
}
}}
})
Other Collection Functions
db.coll.stats()
db.coll.storageSize()
db.coll.totalIndexSize()
db.coll.totalSize()
db.coll.validate({full: true})
db.coll.renameCollection("new_coll", true) // 2nd parameter to drop the target collection if exists
Indexes
Basics
List
db.coll.getIndexes()
db.coll.getIndexKeys()
Drop Indexes
db.coll.dropIndex("name_1")
Hide/Unhide Indexes
db.coll.hideIndex("name_1")
db.coll.unhideIndex("name_1")
Create Indexes
// Index Types
db.coll.createIndex({"name": 1}) // single field index
db.coll.createIndex({"name": 1, "date": 1}) // compound index
db.coll.createIndex({foo: "text", bar: "text"}) // text index
db.coll.createIndex({"$**": "text"}) // wildcard text index
db.coll.createIndex({"userMetadata.$**": 1}) // wildcard index
db.coll.createIndex({"loc": "2d"}) // 2d index
db.coll.createIndex({"loc": "2dsphere"}) // 2dsphere index
db.coll.createIndex({"_id": "hashed"}) // hashed index
// Index Options
db.coll.createIndex({"lastModifiedDate": 1}, {expireAfterSeconds: 3600}) // TTL index
db.coll.createIndex({"name": 1}, {unique: true})
db.coll.createIndex({"name": 1}, {partialFilterExpression: {age: {$gt: 18}}}) // partial index
db.coll.createIndex({"name": 1}, {collation: {locale: 'en', strength: 1}}) // case insensitive index with strength = 1 or 2
db.coll.createIndex({"name": 1 }, {sparse: true})
Others
Handy commands
use admin
db.createUser({"user": "root", "pwd": passwordPrompt(), "roles": ["root"]})
db.dropUser("root")
db.auth( "user", passwordPrompt() )
use test
db.getSiblingDB("dbname")
db.currentOp()
db.killOp(123) // opid
db.fsyncLock()
db.fsyncUnlock()
db.getCollectionNames()
db.getCollectionInfos()
db.printCollectionStats()
db.stats()
db.getReplicationInfo()
db.printReplicationInfo()
db.isMaster()
db.hostInfo()
db.printShardingStatus()
db.shutdownServer()
db.serverStatus()
db.setSlaveOk()
db.getSlaveOk()
db.getProfilingLevel()
db.getProfilingStatus()
db.setProfilingLevel(1, 200) // 0 == OFF, 1 == ON with slowms, 2 == ON
db.enableFreeMonitoring()
db.disableFreeMonitoring()
db.getFreeMonitoringStatus()
db.createView("viewName", "sourceColl", [{$project:{department: 1}}])
Replica Set
rs.status()
rs.initiate({"_id": "replicaTest",
members: [
{ _id: 0, host: "127.0.0.1:27017" },
{ _id: 1, host: "127.0.0.1:27018" },
{ _id: 2, host: "127.0.0.1:27019", arbiterOnly:true }]
})
rs.add("mongodbd1.example.net:27017")
rs.addArb("mongodbd2.example.net:27017")
rs.remove("mongodbd1.example.net:27017")
rs.conf()
rs.isMaster()
rs.printReplicationInfo()
rs.printSlaveReplicationInfo()
rs.reconfig(<valid_conf>)
rs.slaveOk()
rs.stepDown(20, 5) // (stepDownSecs, secondaryCatchUpPeriodSecs)
Sharded Cluster
sh.status()
sh.addShard("rs1/mongodbd1.example.net:27017")
sh.shardCollection("mydb.coll", {zipcode: 1})
sh.moveChunk("mydb.coll", { zipcode: "53187" }, "shard0019")
sh.splitAt("mydb.coll", {x: 70})
sh.splitFind("mydb.coll", {x: 70})
sh.disableAutoSplit()
sh.enableAutoSplit()
sh.startBalancer()
sh.stopBalancer()
sh.disableBalancing("mydb.coll")
sh.enableBalancing("mydb.coll")
sh.getBalancerState()
sh.setBalancerState(true/false)
sh.isBalancerRunning()
sh.addTagRange("mydb.coll", {state: "NY", zip: MinKey }, { state: "NY", zip: MaxKey }, "NY")
sh.removeTagRange("mydb.coll", {state: "NY", zip: MinKey }, { state: "NY", zip: MaxKey }, "NY")
sh.addShardTag("shard0000", "NYC")
sh.removeShardTag("shard0000", "NYC")
sh.addShardToZone("shard0000", "JFK")
sh.removeShardFromZone("shard0000", "NYC")
sh.removeRangeFromZone("mydb.coll", {a: 1, b: 1}, {a: 10, b: 10})
Change Streams
watchCursor = db.coll.watch( [ { $match : {"operationType" : "insert" } } ] )
while (!watchCursor.isExhausted()){
if (watchCursor.hasNext()){
print(tojson(watchCursor.next()));
}
}