MongoDB.md

sudo systemctl start mongod

sudo systemctl status mongod

sudo systemctl stop mongod

sudo systemctl enable mongod // tự động bặt servẻ khi khởi động máy

sudo systemctl restart mongod

mongo // mở mongo giao diện terminal

db.help() // mở bảng hướng dẫn các lệnh

show dbs //xem database và dung lượng

use Name_data // để truy cập vào database

db //kiểm tra đang sử dụng database nào

Database

Select Database

use DATABASE_NAME

Example

> use mydb
switched to db mydb

Check selected database

> show dbs
admin  0.000GB
local  0.000GB
test   0.000GB

Create Database

Create database by insert of first document.

switched to db mydb
> db.pets.insert({name: 'Pista', kind: 'dog'})
WriteResult({ "nInserted" : 1 })
> show dbs
admin  0.000GB
local  0.000GB
mydb   0.000GB
test   0.000GB

Drop Database

> db.dropDatabase()
{ "dropped" : "mydb", "ok" : 1 }
> show dbs
admin  0.000GB
local  0.000GB
test   0.000GB

Collection

Create Collection

> use test
switched to db test
> db.createCollection("mycol")
{ "ok" : 1 }
> db.createCollection("cappedcol", {
    capped: true,
    autoIndexID: true,
    size: 1024,
    max: 1
})
{ "ok" : 1 }

List collections

> show collections
mycol
crappedcol

Rename Collection

> db.mycol.renameCollection('newcol')
{ "ok" : 1 }

Drop Collection

> db.mycol.drop()
true

Insert Document

> db.COLLECTION_NAME.insert(DOCUMENT)

Example

db.pets.insert({
    name: 'Fista',
    kind: 'cat',
    age: 2,
    colors: ['black', 'white'],
})
db.pets.insert({
    name: 'Pista',
    kind: 'dog',
    age: 4,
    colors: ['brown'],
})
db.pets.insert({
    name: 'Ben',
    kind: 'dog',
    age: 12,
    colors: ['white'],
})
db.pets.insert({
    name: 'Mista',
    kind: 'rat',
    age: 1,
    colors: ['black', 'brown'],
})

Query Document

Find

Select all documents

> db.COLLECTION_NAME.find()

or

> db.COLLECTION_NAME.find({})

Example

> db.pets.find()
{ "_id" : ObjectId("58dc747ad3fbf12faaaa1706"), "name" : "Fista", "kind" : "cat", "age" : 2, "colors" : [ "black", "white" ] }
{ "_id" : ObjectId("58dc74e4d3fbf12faaaa1707"), "name" : "Pista", "kind" : "dog", "age" : 4, "colors" : [ "brown" ] }
{ "_id" : ObjectId("58dc74e4d3fbf12faaaa1708"), "name" : "Mista", "kind" : "rat", "age" : 1, "colors" : [ "black", "brown" ] }

For pretty formating, use .pretty()

> db.pets.find().pretty()
{
	"_id" : ObjectId("58dc747ad3fbf12faaaa1706"),
	"name" : "Fista",
	"kind" : "cat",
	"age" : 2,
	"colors" : [
		"black",
		"white"
	]
}
...

Operators

• List of all operators - see docs - https://docs.mongodb.com/manual/reference/operator/query/

Operation	Syntax	Example	SQL
Equality	{<key>:<value>}	{kind: 'rat'}	where kind = 'rat'
Less Than	{<key>:{$lt:<value>}}	{age: {$lt: 2}}	where age < 2
Less Than Equals	{<key>:{$lte:<value>}}	{age: {$lte: 2}}	where age <= 2
Greater Than	{<key>:{$gt:<value>}}	{age: {$gt: 2}}	where age > 2
Greater Than Equals	{<key>:{$gte:<value>}}	{age: {$gte: 2}}	where age >= 2
Not Equals	{<key>:{$ne:<value>}}	{age: {$ne: 2}}	where age != 2
In	{<key>:{$in:[<value1>, <value2>, ...]}}	{age: {$in: [1, 2, 3]}}	where age in (1, 2, 3)

Examples

> db.pets.find({name: 'Pista'})
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170a"), "name" : "Pista", "kind" : "dog", "age" : 4, "colors" : [ "brown" ] }
> db.pets.find({kind: 'dog'})
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170a"), "name" : "Pista", "kind" : "dog", "age" : 4, "colors" : [ "brown" ] }
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170b"), "name" : "Ben", "kind" : "dog", "age" : 12, "colors" : [ "white" ] }
> db.pets.find({colors: 'black'})
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170c"), "name" : "Mista", "kind" : "rat", "age" : 1, "colors" : [ "black", "brown" ] }
{ "_id" : ObjectId("58dc7f6cd3fbf12faaaa170d"), "name" : "Fista", "kind" : "cat", "age" : 2, "colors" : [ "black", "white" ] }
> db.pets.find({colors: {$ne: 'black'}})
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170a"), "name" : "Pista", "kind" : "dog", "age" : 4, "colors" : [ "brown" ] }
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170b"), "name" : "Ben", "kind" : "dog", "age" : 12, "colors" : [ "white" ] }

Columns

db.COLLECTION_NAME.find(QUERY, COLLUMNS)

Example

> db.pets.find({}, {name: 1})
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170a"), "name" : "Pista" }
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170b"), "name" : "Ben" }
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170c"), "name" : "Mista" }
{ "_id" : ObjectId("58dc7f6cd3fbf12faaaa170d"), "name" : "Fista" }
> db.pets.find({}, {name: 1, _id: 0})
{ "name" : "Pista" }
{ "name" : "Ben" }
{ "name" : "Mista" }
{ "name" : "Fista" }
> db.pets.find({}, {_id: 0})
{ "name" : "Pista", "kind" : "dog", "age" : 4, "colors" : [ "brown" ] }
{ "name" : "Ben", "kind" : "dog", "age" : 12, "colors" : [ "white" ] }
{ "name" : "Mista", "kind" : "rat", "age" : 1, "colors" : [ "black", "brown" ] }
{ "name" : "Fista", "kind" : "cat", "age" : 2, "colors" : [ "black", "white" ] }

AND

db.COLLECTION_NAME.find({key1:value1, key2:value2})

Example

> db.pets.find({age: {$gte: 2}, kind: 'dog'})
{ "_id" : ObjectId("58dc74e4d3fbf12faaaa1707"), "name" : "Pista", "kind" : "dog", "age" : 4, "colors" : [ "brown" ] }

OR

db.COLLECTION_NAME.find({$or: [{key1: value1}, {key2:value2}]})

Example

> db.pets.find({$or: [{kind: 'rat'}, {kind: 'cat'}]})
{ "_id" : ObjectId("58dc747ad3fbf12faaaa1706"), "name" : "Fista", "kind" : "cat", "age" : 2, "colors" : [ "black", "white" ] }
{ "_id" : ObjectId("58dc74e4d3fbf12faaaa1708"), "name" : "Mista", "kind" : "rat", "age" : 1, "colors" : [ "black", "brown" ] }

Limit & Offset

> db.pets.find().limit(1)
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170a"), "name" : "Pista", "kind" : "dog", "age" : 4, "colors" : [ "brown" ] }
> db.pets.find().skip(1)
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170b"), "name" : "Ben", "kind" : "dog", "age" : 12, "colors" : [ "white" ] }
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170c"), "name" : "Mista", "kind" : "rat", "age" : 1, "colors" : [ "black", "brown" ] }
{ "_id" : ObjectId("58dc7f6cd3fbf12faaaa170d"), "name" : "Fista", "kind" : "cat", "age" : 2, "colors" : [ "black", "white" ] }
> db.pets.find().skip(1).limit(1)
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170b"), "name" : "Ben", "kind" : "dog", "age" : 12, "colors" : [ "white" ] }

Sort

> db.pets.find().sort({name: 1})
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170b"), "name" : "Ben", "kind" : "dog", "age" : 12, "colors" : [ "white" ] }
{ "_id" : ObjectId("58dc7f6cd3fbf12faaaa170d"), "name" : "Fista", "kind" : "cat", "age" : 2, "colors" : [ "black", "white" ] }
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170c"), "name" : "Mista", "kind" : "rat", "age" : 1, "colors" : [ "black", "brown" ] }
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170a"), "name" : "Pista", "kind" : "dog", "age" : 4, "colors" : [ "brown" ] }
> db.pets.find().sort({name: -1} )
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170a"), "name" : "Pista", "kind" : "dog", "age" : 4, "colors" : [ "brown" ] }
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170c"), "name" : "Mista", "kind" : "rat", "age" : 1, "colors" : [ "black", "brown" ] }
{ "_id" : ObjectId("58dc7f6cd3fbf12faaaa170d"), "name" : "Fista", "kind" : "cat", "age" : 2, "colors" : [ "black", "white" ] }
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170b"), "name" : "Ben", "kind" : "dog", "age" : 12, "colors" : [ "white" ] }
> 

Update Documents

db.COLLECTION_NAME.update(SELECTIOIN_CRITERIA, UPDATED_DATA)

Example

> db.pets.update({name: 'Ben'}, {$set: {age: 13}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.pets.find({name: 'Ben'})
{ "_id" : ObjectId("58dc7af7d3fbf12faaaa1709"), "name" : "Ben", "kind" : "dog", "age" : 13, "colors" : [ "white" ] }

By default, MongoDB will update only a single document. To update multiple documents, you need to set a parameter 'multi' to true.

db.COLLECTION_NAME.update(SELECTIOIN_CRITERIA, UPDATED_DATA, {multi: true})

Example

> db.pets.update({name: 'Ben'}, {$set: {age: 13}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.pets.find({name: 'Ben'})
{ "_id" : ObjectId("58dc7af7d3fbf12faaaa1709"), "name" : "Ben", "kind" : "dog", "age" : 13, "colors" : [ "white" ] }

Save

Replace document by ID

db.COLLECTION_NAME.save({_id:ObjectId(),NEW_DATA})

Example

> db.pets.find({_id: ObjectId('58dc7af7d3fbf12faaaa1709')})
{ "_id" : ObjectId("58dc7af7d3fbf12faaaa1709"), "name" : "Ben", "kind" : "dog", "age" : 13, "colors" : [ "white" ] }
> db.pets.save({ "_id" : ObjectId("58dc7af7d3fbf12faaaa1709"), "name" : 
> db.pets.save({ "_id" : ObjectId("58dc7af7d3fbf12faaaa1709"), "name" : "Benik", "kind" : "dog", "age" : 11 })
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.pets.find({_id: ObjectId('58dc7af7d3fbf12faaaa1709')})
{ "_id" : ObjectId("58dc7af7d3fbf12faaaa1709"), "name" : "Benik", "kind" : "dog", "age" : 11 }

Deleting Documents

Work only with non-capped collections.

db.COLLECTION_NAME.remove(DELLETION_CRITTERIA)

Remove only one

db.COLLECTION_NAME.remove(DELLETION_CRITTERIA, 1)

Example

> db.pets.find()
{ "_id" : ObjectId("58dc747ad3fbf12faaaa1706"), "name" : "Fista", "kind" : "cat", "age" : 2, "colors" : [ "black", "white" ] }
{ "_id" : ObjectId("58dc74e4d3fbf12faaaa1707"), "name" : "Pista", "kind" : "dog", "age" : 4, "colors" : [ "brown" ] }
{ "_id" : ObjectId("58dc74e4d3fbf12faaaa1708"), "name" : "Mista", "kind" : "rat", "age" : 1, "colors" : [ "black", "brown" ] }
{ "_id" : ObjectId("58dc7af7d3fbf12faaaa1709"), "name" : "Benik", "kind" : "dog", "age" : 11 }
> db.pets.remove({age: {$gt: 1}}, 1)
WriteResult({ "nRemoved" : 1 })
> db.pets.remove({age: {$gt: 1}})
WriteResult({ "nRemoved" : 2 })
> db.pets.find()
{ "_id" : ObjectId("58dc74e4d3fbf12faaaa1708"), "name" : "Mista", "kind" : "rat", "age" : 1, "colors" : [ "black", "brown" ] }

Delete all documents

db.COLLECTION_NAME.remove({})

Example

> db.pets.remove({})
WriteResult({ "nRemoved" : 1 })

Indexing

Get indexes

db.COLLECTION.getIndexes()

Example

> db.pets.getIndexes()
[
	{
		"v" : 1,
		"key" : {
			"_id" : 1
		},
		"name" : "_id_",
		"ns" : "test.pets"
	}
]

Create index

db.COLLECTION_NAME.ensureIndex({KEY:1})

or multi key index

db.COLLECTION_NAME.ensureIndex({KEY1:1, KEY2:1})

Examples:

> db.pets.ensureIndex({age:1})
{
	"createdCollectionAutomatically" : false,
	"numIndexesBefore" : 1,
	"numIndexesAfter" : 2,
	"ok" : 1
}

Parameters:

db.COLLECTION_NAME.ensureIndex(INDEX, PARAMS)

Eg.:

db.COLLECTION_NAME.ensureIndex(INDEX, {
    unique: 1,
    backgroud: 1,
})

Background means build index on background, don't block the DB.

Example:

> db.pets.ensureIndex({name: 1}, {
    unique: 1,
    backgroud: 1,
})
> db.pets.find()
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170a"), "name" : "Pista", "kind" : "dog", "age" : 4, "colors" : [ "brown" ] }
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170b"), "name" : "Ben", "kind" : "dog", "age" : 12, "colors" : [ "white" ] }
{ "_id" : ObjectId("58dc7f1fd3fbf12faaaa170c"), "name" : "Mista", "kind" : "rat", "age" : 1, "colors" : [ "black", "brown" ] }
{ "_id" : ObjectId("58dc7f6cd3fbf12faaaa170d"), "name" : "Fista", "kind" : "cat", "age" : 2, "colors" : [ "black", "white" ] }
> db.pets.insert({name: 'Pista', kind: 'bat'})
WriteResult({
	"nInserted" : 0,
	"writeError" : {
		"code" : 11000,
		"errmsg" : "E11000 duplicate key error collection: test.pets index: name_1 dup key: { : \"Pista\" }"
	}
})

Drop index

db.COLLECTION_NAME.dropIndex({KEY:1})

Example

> db.pets.dropIndex({age:1})
{ "nIndexesWas" : 3, "ok" : 1 }

Count

db.COLLECTION_NAME.count()

or

db.COLLECTION_NAME.find(QUERY).count()

Example

> db.pets.count()
4
> db.pets.find({kind: 'dog'})
2

Aggregation

aggregation operators

• $sum
• $avg
• $min
• $max
• $push
• $addToSet
• $first
• $last

Example

> db.pets.aggregate([{$group : {_id : "$kind", count: {$sum : 1}}}])
{ "_id" : "cat", "count" : 1 }
{ "_id" : "rat", "count" : 1 }
{ "_id" : "dog", "count" : 2 }
> db.pets.aggregate([{$group : {_id : "$kind", count: {$sum : 1}, age: {$avg: '$age'}}}])
{ "_id" : "cat", "count" : 1, "age" : 2 }
{ "_id" : "rat", "count" : 1, "age" : 1 }
{ "_id" : "dog", "count" : 2, "age" : 8 }

By multiple keys

> db.pets.aggregate([{$group : {_id : {kind: '$kind', age: '$age'}, count: {$sum : 1}}}])
{ "_id" : { "kind" : "cat", "age" : 2 }, "count" : 1 }
{ "_id" : { "kind" : "rat", "age" : 1 }, "count" : 1 }
{ "_id" : { "kind" : "dog", "age" : 12 }, "count" : 1 }
{ "_id" : { "kind" : "dog", "age" : 4 }, "count" : 1 }