MongoDBのクエリの備忘録 (Element)

mongodb

準備

使用するMongoDBはこちらと同じ。
MongoDB Shellで接続して、マニュアルと同じテストデータを挿入する。

test> db.inventory.insertMany([
...  { item: "journal", qty: 25, tags: ["blank", "red"], dim_cm: [ 14, 21 ] },
...  { item: "notebook", qty: 50, tags: ["red", "blank"], dim_cm: [ 14, 21 ] },
...  { item: "paper", qty: 100, tags: ["red", "blank", "plain"], dim_cm: [ 14, 21 ] },
...  { item: "planner", qty: 75, tags: ["blank", "red"], dim_cm: [ 22.85, 30 ] },
...  { item: "postcard", qty: 45, tags: ["blue"], dim_cm: [ 10, 15.25 ] }
...  ]);
{
  acknowledged: true,
  insertedIds: {
    '0': ObjectId("63945c181ce8aac5f4f6e632"),
    '1': ObjectId("63945c181ce8aac5f4f6e633"),
    '2': ObjectId("63945c181ce8aac5f4f6e634"),
    '3': ObjectId("63945c181ce8aac5f4f6e635"),
    '4': ObjectId("63945c181ce8aac5f4f6e636")
  }
}

テストデータを変更して、"notebook"のqty fieldを削除、"paper"のqtyにnullを設定する。

test> db.inventory.updateOne({item: "notebook"}, {$unset: {qty: ""}})
{
  acknowledged: true,
  insertedId: null,
  matchedCount: 1,
  modifiedCount: 1,
  upsertedCount: 0
}

test> db.inventory.updateOne({item: "paper"}, {$set: {qty: undefined}})
{
  acknowledged: true,
  insertedId: null,
  matchedCount: 1,
  modifiedCount: 1,
  upsertedCount: 0
}

Element Query Operators

exists

qty fieldがあるdocumentを取得
（valueがnullのdocumentも含む）

test> db.inventory.find({qty: {$exists: true}})
[
  {
    _id: ObjectId("63945c181ce8aac5f4f6e632"),
    item: 'journal',
    qty: 25,
    tags: [ 'blank', 'red' ],
    dim_cm: [ 14, 21 ]
  },
  {
    _id: ObjectId("63945c181ce8aac5f4f6e634"),
    item: 'paper',
    qty: null,
    tags: [ 'red', 'blank', 'plain' ],
    dim_cm: [ 14, 21 ]
  },
  {
    _id: ObjectId("63945c181ce8aac5f4f6e635"),
    item: 'planner',
    qty: 75,
    tags: [ 'blank', 'red' ],
    dim_cm: [ 22.85, 30 ]
  },
  {
    _id: ObjectId("63945c181ce8aac5f4f6e636"),
    item: 'postcard',
    qty: 45,
    tags: [ 'blue' ],
    dim_cm: [ 10, 15.25 ]
  }
]

qty fieldがないdocumentを取得

test> db.inventory.find({qty: {$exists: false}})
[
  {
    _id: ObjectId("63945c181ce8aac5f4f6e633"),
    item: 'notebook',
    tags: [ 'red', 'blank' ],
    dim_cm: [ 14, 21 ]
  }
]

type

qtyのvalueがnumberのdocumentを取得

test> db.inventory.find({qty: {$type: "number"}})
[
  {
    _id: ObjectId("63945c181ce8aac5f4f6e632"),
    item: 'journal',
    qty: 25,
    tags: [ 'blank', 'red' ],
    dim_cm: [ 14, 21 ]
  },
  {
    _id: ObjectId("63945c181ce8aac5f4f6e635"),
    item: 'planner',
    qty: 75,
    tags: [ 'blank', 'red' ],
    dim_cm: [ 22.85, 30 ]
  },
  {
    _id: ObjectId("63945c181ce8aac5f4f6e636"),
    item: 'postcard',
    qty: 45,
    tags: [ 'blue' ],
    dim_cm: [ 10, 15.25 ]
  }
]

qtyのvalueがnullのdocumentを取得

test> db.inventory.find({qty: {$type: "null"}})
[
  {
    _id: ObjectId("63945c181ce8aac5f4f6e634"),
    item: 'paper',
    qty: null,
    tags: [ 'red', 'blank', 'plain' ],
    dim_cm: [ 14, 21 ]
  }
]

参考