ドットインストール：MongoDB入門

用語

Database > Collection > Document

DocumentはRDBでいうレコード

スキーマレスなのでキーが異なってもいい

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Database

作成

コレクションを作成しない限り一覧には表示されない

一覧

show dbs

削除

db.dropDatabase()

現在のDBの情報

db.stats()

DBの読み込み

Collection

作成

db.createCollection("COLLECTION_NAME")

一覧

show collections

削除

db.NAME.drop()

リネーム

db.OLD_NAME.renameCollection("NEW_NAME")

Document

作成

code:zsh

db.members.insert(

... {name: "gaku",

... age:17}

... );

collectionがなくてもこのようにinsertすれば自動的に生成される

同じkey-valueの組み合わせのデータも別物（idが別）として扱われる

一覧

db.COLLECTION_NAME.find()

削除

db.COLLECTION_NAME.remove({}) // 全件削除

Collectionに含まれるドキュメントの数

db.COLLECTION_NAME.count()

JavaScriptの構文が使える

ユニークなidが自動で振られる

find()をほりさげる

準備

てきとーなデータセット（適当すぎて適切ではないし内容も間違ってる…）

code:zsh

db.members.find()

{ "_id" : ObjectId("5b3ba2c8fc7416f3f09981e8"), "name" : "gaku", "age" : 17 }

{ "_id" : ObjectId("5b3ba6af7182e81d5187fb8f"), "name" : "ago", "age" : 17 }

{ "_id" : ObjectId("5b3ba6b37182e81d5187fb90"), "name" : "iincho", "age" : 17 }

{ "_id" : ObjectId("5b3ba6b77182e81d5187fb91"), "name" : "dero", "age" : 17 }

{ "_id" : ObjectId("5b3ba6bb7182e81d5187fb92"), "name" : "dero", "age" : 18 }

{ "_id" : ObjectId("5b3ba6c47182e81d5187fb93"), "name" : "dero", "age" : 18 }

特定のKey-valueに一致するものだけ表示

code:zsh

db.members.find({age: 18})

{ "_id" : ObjectId("5b3ba6bb7182e81d5187fb92"), "name" : "dero", "age" : 18 }

{ "_id" : ObjectId("5b3ba6c47182e81d5187fb93"), "name" : "dero", "age" : 18 }

比較

code:zsh

db.members.find({age: {$gte: 18}})

{ "_id" : ObjectId("5b3ba6bb7182e81d5187fb92"), "name" : "dero", "age" : 18 }

{ "_id" : ObjectId("5b3ba6c47182e81d5187fb93"), "name" : "dero", "age" : 18 }

code:zsh

db.members.find({name: /go/})

{ "_id" : ObjectId("5b3ba6af7182e81d5187fb8f"), "name" : "ago", "age" : 17 }

キー名の抽出

nameの一覧が見たい

code:zsh

db.members.distinct("name")

AND検索

code:zsh

db.members.find({name: /dero/, age: 17})

{ "_id" : ObjectId("5b3ba6b77182e81d5187fb91"), "name" : "dero", "age" : 17 }

OR検索

code:zsh

{ "_id" : ObjectId("5b3ba6af7182e81d5187fb8f"), "name" : "ago", "age" : 17 }

{ "_id" : ObjectId("5b3ba6b37182e81d5187fb90"), "name" : "iincho", "age" : 17 }

キーの中の複数の特定の値

code:zsh

{ "_id" : ObjectId("5b3ba2c8fc7416f3f09981e8"), "name" : "gaku", "age" : 17 }

{ "_id" : ObjectId("5b3ba6af7182e81d5187fb8f"), "name" : "ago", "age" : 17 }

要素の有無

code:zsh

# 要素追加

db.members.insert({"name":"eru", "age":240, "ikiri":true})

# ikiriが存在してるドキュメントだけ抽出

db.members.find({ikiri:{$exists:true}})

{ "_id" : ObjectId("5b3bb0af7182e81d5187fb94"), "name" : "eru", "age" : 240, "ikiri" : true }

フィールドの表示

第二引数で表示したいフィールドを指定できる

code:zsh

db.members.find({}, {name:true})

{ "_id" : ObjectId("5b3ba2c8fc7416f3f09981e8"), "name" : "gaku" }

{ "_id" : ObjectId("5b3ba6af7182e81d5187fb8f"), "name" : "ago" }

{ "_id" : ObjectId("5b3ba6b37182e81d5187fb90"), "name" : "iincho" }

{ "_id" : ObjectId("5b3ba6b77182e81d5187fb91"), "name" : "dero" }

{ "_id" : ObjectId("5b3ba6bb7182e81d5187fb92"), "name" : "dero" }

{ "_id" : ObjectId("5b3ba6c47182e81d5187fb93"), "name" : "dero" }

{ "_id" : ObjectId("5b3bb0af7182e81d5187fb94"), "name" : "eru" }

0と1は混在できない

code:zsh

db.members.find({}, {name:0, age:1})

Error: error: {

"ok" : 0,

"errmsg" : "Projection cannot have a mix of inclusion and exclusion.",

"code" : 2,

"codeName" : "BadValue"

}

ソート

年齢でソートする

code:zsh

db.members.find({}, {_id: 0}).sort({age: 1})

{ "name" : "gaku", "age" : 17 }

{ "name" : "ago", "age" : 17 }

{ "name" : "iincho", "age" : 17 }

{ "name" : "dero", "age" : 17 }

{ "name" : "dero", "age" : 18 }

{ "name" : "dero", "age" : 18 }

{ "name" : "eru", "age" : 240, "ikiri" : true }

1は昇順。0は降順

skipで前半を飛ばす

code:zsh

db.members.find({}, {_id: 0}).sort({age: 1}).skip(5)

{ "name" : "dero", "age" : 18 }

{ "name" : "eru", "age" : 240, "ikiri" : true }

limit

code:zsh

db.members.find({}, {_id: 0}).sort({age: 1}).limit(1)

{ "name" : "gaku", "age" : 17 }

limit(1)はfindOneと同じ

code:zsh

db.members.findOne({}, {_id: 0})

{ "name" : "gaku", "age" : 17 }

ドキュメントの更新

code:zsh

db.members.update({name: "ago"}, {$set: {"age":27, "song":"sharpnes..."}})

WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

db.members.find({name: "ago"})

{ "_id" : ObjectId("5b3ba6af7182e81d5187fb8f"), "name" : "ago", "age" : 27, "song" : "sharpnes..." }

code:zsh

db.members.update({name: "ago"}, {"name": "rikiya"})

WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

db.members.find({name: "ago"}) # そんなレコードはもうない

db.members.find({name: "rikiya"})

{ "_id" : ObjectId("5b3ba6af7182e81d5187fb8f"), "name" : "rikiya" }

💣抽出条件に合致するものは1つのレコードしか更新されない

code:zsh

db.members.update({name: "dero"}, {$set: {"age":27}})

WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

db.members.find({name: "dero"})

{ "_id" : ObjectId("5b3ba6b77182e81d5187fb91"), "name" : "dero", "age" : 27 }

{ "_id" : ObjectId("5b3ba6bb7182e81d5187fb92"), "name" : "dero", "age" : 18 }

{ "_id" : ObjectId("5b3ba6c47182e81d5187fb93"), "name" : "dero", "age" : 18 }

code:zsh

db.members.update({name: "dero"}, {$set: {"age":27}}, {multi:true})

WriteResult({ "nMatched" : 3, "nUpserted" : 0, "nModified" : 2 })

db.members.find({name: "dero"})

{ "_id" : ObjectId("5b3ba6b77182e81d5187fb91"), "name" : "dero", "age" : 27 }

{ "_id" : ObjectId("5b3ba6bb7182e81d5187fb92"), "name" : "dero", "age" : 27 }

{ "_id" : ObjectId("5b3ba6c47182e81d5187fb93"), "name" : "dero", "age" : 27 }

現在の値をもとに更新する（インクリメントとか）

使い方は↑と同じ

情報があったらupdate、なかったら追加

$upsert

update or insert。条件に一致するものがあればupdate、なければinsert

通常のupdateは条件に一致するものがなければ何も行われない

code:zsh

# 普通にupdateしてもマッチしなければ何も起きない

db.members.update({"name":"kazaki"}, {"name":"kazaki", "age": 9})

WriteResult({ "nMatched" : 0, "nUpserted" : 0, "nModified" : 0 })

# upsertをつけると作成される

db.members.update({"name":"kazaki"}, {"name":"kazaki", "age": 9}, {upsert: true})

WriteResult({

"nMatched" : 0,

"nUpserted" : 1,

"nModified" : 0,

"_id" : ObjectId("5b3bc91a6eea69d87b7a82a3")

})

db.members.find({"name":"kazaki"})

{ "_id" : ObjectId("5b3bc91a6eea69d87b7a82a3"), "name" : "kazaki", "age" : 9 }

# マッチしたら更新される

db.members.update({"name":"kazaki"}, {"name":"kazaki", "age": 99}, {upsert: true})

WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

db.members.find({"name":"kazaki"})

{ "_id" : ObjectId("5b3bc91a6eea69d87b7a82a3"), "name" : "kazaki", "age" : 99 }

Indexをフィールドにはる

いまはられてるのは？

code:zsh

db.members.getIndexes()

[

{

"v" : 2,

"key" : {

"_id" : 1

},

"name" : "_id_",

"ns" : "nijisanji.members"

}

]

idのindexを消すことはできない

indexの作成

降順 -1, 昇順 1

code:zsh

db.members.createIndex({age: -1});

{

"createdCollectionAutomatically" : false,

"numIndexesBefore" : 1,

"numIndexesAfter" : 2,

"ok" : 1

}

db.members.getIndexes()

[

{

"v" : 2,

"key" : {

"_id" : 1

},

"name" : "_id_",

"ns" : "nijisanji.members"

},

{

"v" : 2,

"key" : {

"age" : -1

},

"name" : "age_-1",

"ns" : "nijisanji.members"

}

]

削除

nameを渡す

code:zsh

db.members.dropIndex("age_-1")

{ "nIndexesWas" : 2, "ok" : 1 }

uniqueキーを付ける

code:zsh

# すでに重複してるからuniqueをつけることができない

db.members.createIndex({name: 1}, {unique: true})

{

"ok" : 0,

"errmsg" : "E11000 duplicate key error collection: nijisanji.members index: name_1 dup key: { : \"dero\" }",

"code" : 11000,

"codeName" : "DuplicateKey"

}

重複を消して↑を実行すれば重複した名前をinsertしようとしたときにエラーになる

aggregateを使って削除する

バックアップと復元

code:zsh

# --dropをつけないと重複したドキュメントの更新に失敗する（重複していないものはリストアされる）

$ mongorestore

2018-07-03T19:31:44.593+0000 using default 'dump' directory

2018-07-03T19:31:44.594+0000 preparing collections to restore from

2018-07-03T19:31:44.605+0000 reading metadata for nijisanji.members from dump/nijisanji/members.metadata.json

2018-07-03T19:31:44.606+0000 restoring nijisanji.members from dump/nijisanji/members.bson

2018-07-03T19:31:44.618+0000 error: multiple errors in bulk operation:

- E11000 duplicate key error collection: nijisanji.members index: _id_ dup key: { : ObjectId('5b3ba2c8fc7416f3f09981e8') }

- E11000 duplicate key error collection: nijisanji.members index: _id_ dup key: { : ObjectId('5b3ba6af7182e81d5187fb8f') }

- E11000 duplicate key error collection: nijisanji.members index: _id_ dup key: { : ObjectId('5b3ba6b37182e81d5187fb90') }

- E11000 duplicate key error collection: nijisanji.members index: _id_ dup key: { : ObjectId('5b3ba6b77182e81d5187fb91') }

- E11000 duplicate key error collection: nijisanji.members index: _id_ dup key: { : ObjectId('5b3ba6bb7182e81d5187fb92') }

- E11000 duplicate key error collection: nijisanji.members index: _id_ dup key: { : ObjectId('5b3ba6c47182e81d5187fb93') }

- E11000 duplicate key error collection: nijisanji.members index: _id_ dup key: { : ObjectId('5b3bb0af7182e81d5187fb94') }

- E11000 duplicate key error collection: nijisanji.members index: _id_ dup key: { : ObjectId('5b3bc91a6eea69d87b7a82a3') }

2018-07-03T19:31:44.618+0000 no indexes to restore

2018-07-03T19:31:44.618+0000 finished restoring nijisanji.members (8 documents)

2018-07-03T19:31:44.619+0000 done

# dropをつける

$ mongorestore --drop

2018-07-03T19:32:39.318+0000 using default 'dump' directory

2018-07-03T19:32:39.318+0000 preparing collections to restore from

2018-07-03T19:32:39.331+0000 reading metadata for nijisanji.members from dump/nijisanji/members.metadata.json

2018-07-03T19:32:39.359+0000 restoring nijisanji.members from dump/nijisanji/members.bson

2018-07-03T19:32:39.374+0000 no indexes to restore

2018-07-03T19:32:39.376+0000 finished restoring nijisanji.members (8 documents)

2018-07-03T19:32:39.378+0000 done