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$setField (aggregation)

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定義

$setField

バージョン 5.0 で追加

ドキュメント内の指定フィールドを追加、アップデート、排除します。

You can use $setField to add, update, or remove fields with names that contain periods (.) or start with dollar signs ($).

Tip

使用 $getField to retrieve the values of fields that contain dollar signs ($) or periods (.) that you add or update with $setField.

構文

$setFieldの構文は次のとおりです。

{
  $setField: {
    field: <String>,
    input: <Object>,
    value: <Expression>
  }
}

You must provide the following fields:

フィールド
タイプ
説明

field

文字列

Field in the input object that you want to add, update, or remove. field can be any valid 式 that resolves to a string constant.

input

オブジェクト

Document that contains the field that you want to add or update. input must resolve to an object, missing, null, or undefined.

value

式

The value that you want to assign to field. value can be any valid 式.

Set to $$REMOVE to remove field from the input document.

動作

  • If input evaluates to missing, undefined, or null, $setField returns null and does not update input.

  • inputがオブジェクト以外のオブジェクト（ missing 、 undefined 、またはnull ）以外と評価された場合、 $setFieldはエラーを返します。

  • If field resolves to anything other than a string constant, $setField returns an error.

  • If field doesn't exist in input, $setField adds it.

  • $setField doesn't implicitly traverse objects or arrays. For example, $setField evaluates a field value of "a.b.c" as a top-level field "a.b.c" instead of as a nested field, { "a": { "b": { "c": } } }.

  • $unsetField is an alias for $setField with an input value of $$REMOVE. The following expressions are equivalent:

    {
       $setField: {
          field: <field name>,
          input: "$$ROOT",
          value: "$$REMOVE"
       }
    }
    {
       $unsetField: {
          field: <field name>,
          input: "$$ROOT"
       }
    }

以下も参照してください。

フィールド名に関する考慮事項

例

Add Fields that Contain Periods (.)

以下のドキュメントを持つinventoryコレクションを検討してください。

db.inventory.insertMany( [
   { "_id" : 1, "item" : "sweatshirt", price: 45.99, qty: 300 }
   { "_id" : 2, "item" : "winter coat", price: 499.99, qty: 200 }
   { "_id" : 3, "item" : "sun dress", price: 199.99, qty: 250 }
   { "_id" : 4, "item" : "leather boots", price: 249.99, qty: 300 }
   { "_id" : 5, "item" : "bow tie", price: 9.99, qty: 180 }
] )

The following operation uses the $replaceWith pipeline stage and the $setField operator to add a new field to each document, "price.usd". The value of "price.usd" will equal the value of "price" in each document. Finally, the operation uses the $unset pipeline stage to remove the "price" field.

db.inventory.aggregate( [
   { $replaceWith: {
        $setField: {
           field: "price.usd",
           input: "$$ROOT",
           value: "$price"
   } } },
   { $unset: "price" }
] )

この操作は次の結果を返します。

[
  { _id: 1, item: 'sweatshirt', qty: 300, 'price.usd': 45.99 },
  { _id: 2, item: 'winter coat', qty: 200, 'price.usd': 499.99 },
  { _id: 3, item: 'sun dress', qty: 250, 'price.usd': 199.99 },
  { _id: 4, item: 'leather boots', qty: 300, 'price.usd': 249.99 },
  { _id: 5, item: 'bow tie', qty: 180, 'price.usd': 9.99 }
]

Add Fields that Start with a Dollar Sign ($)

以下のドキュメントを持つinventoryコレクションを検討してください。

db.inventory.insertMany( [
   { "_id" : 1, "item" : "sweatshirt", price: 45.99, qty: 300 }
   { "_id" : 2, "item" : "winter coat", price: 499.99, qty: 200 }
   { "_id" : 3, "item" : "sun dress", price: 199.99, qty: 250 }
   { "_id" : 4, "item" : "leather boots", price: 249.99, qty: 300 }
   { "_id" : 5, "item" : "bow tie", price: 9.99, qty: 180 }
] )

The following operation uses the $replaceWith pipeline stage and the $setField and $literal operators to add a new field to each document, "$price". The value of "$price" will equal the value of "price" in each document. Finally, the operation uses the $unset pipeline stage to remove the "price" field.

db.inventory.aggregate( [
   { $replaceWith: {
        $setField: {
           field: { $literal: "$price" },
           input: "$$ROOT",
           value: "$price"
   } } },
   { $unset: "price" }
] )

この操作は次の結果を返します。

[
  { _id: 1, item: 'sweatshirt', qty: 300, '$price': 45.99 },
  { _id: 2, item: 'winter coat', qty: 200, '$price': 499.99 },
  { _id: 3, item: 'sun dress', qty: 250, '$price': 199.99 },
  { _id: 4, item: 'leather boots', qty: 300, '$price': 249.99 },
  { _id: 5, item: 'bow tie', qty: 180, '$price': 9.99 }
]

Update Fields that Contain Periods (.)

以下のドキュメントを持つinventoryコレクションを検討してください。

db.inventory.insertMany( [
   { _id: 1, item: 'sweatshirt', qty: 300, 'price.usd': 45.99 },
   { _id: 2, item: 'winter coat', qty: 200, 'price.usd': 499.99 },
   { _id: 3, item: 'sun dress', qty: 250, 'price.usd': 199.99 },
   { _id: 4, item: 'leather boots', qty: 300, 'price.usd': 249.99 },
   { _id: 5, item: 'bow tie', qty: 180, 'price.usd': 9.99 }
] )

The following operation uses the $match pipeline stage to find a specific document and the $replaceWith pipeline stage and the $setField operator to update the "price.usd" field in the matching document:

db.inventory.aggregate( [
   { $match: { _id: 1 } },
   { $replaceWith: {
        $setField: {
           field: "price.usd",
           input: "$$ROOT",
           value: 49.99
    } } }
] )

この操作は次の結果を返します。

[
  { _id: 1, item: 'sweatshirt', qty: 300, 'price.usd': 49.99 }
]

Update Fields that Start with a Dollar Sign ($)

以下のドキュメントを持つinventoryコレクションを検討してください。

db.inventory.insertMany([
   { _id: 1, item: 'sweatshirt', qty: 300, '$price': 45.99 },
   { _id: 2, item: 'winter coat', qty: 200, '$price': 499.99 },
   { _id: 3, item: 'sun dress', qty: 250, '$price': 199.99 },
   { _id: 4, item: 'leather boots', qty: 300, '$price': 249.99 },
   { _id: 5, item: 'bow tie', qty: 180, '$price': 9.99 }
] )

The following operation uses the $match pipeline stage to find a specific document and the $replaceWith pipeline stage and the $setField and $literal operators to update the "$price" field in the matching document:

db.inventory.aggregate( [
   { $match: { _id: 1 } },
   { $replaceWith: {
        $setField: {
           field: { $literal: "$price" },
           input: "$$ROOT",
           value: 49.99
   } } }
] )

この操作は次の結果を返します。

[
  { _id: 1, item: 'sweatshirt', qty: 300, '$price': 49.99 }
]

Remove Fields that Contain Periods (.)

以下のドキュメントを持つinventoryコレクションを検討してください。

db.inventory.insertMany([
   { _id: 1, item: 'sweatshirt', qty: 300, 'price.usd': 45.99 },
   { _id: 2, item: 'winter coat', qty: 200, 'price.usd': 499.99 },
   { _id: 3, item: 'sun dress', qty: 250, 'price.usd': 199.99 },
   { _id: 4, item: 'leather boots', qty: 300, 'price.usd': 249.99 },
   { _id: 5, item: 'bow tie', qty: 180, 'price.usd': 9.99 }
] )

The following operation uses the $replaceWith pipeline stage and the $setField operator and $$REMOVE to remove the "price.usd" field from each document:

db.inventory.aggregate( [
   { $replaceWith:  {
        $setField: {
           field: "price.usd",
           input: "$$ROOT",
           value: "$$REMOVE"
   } } }
] )

この操作は次の結果を返します。

[
  { _id: 1, item: 'sweatshirt', qty: 300 },
  { _id: 2, item: 'winter coat', qty: 200 },
  { _id: 3, item: 'sun dress', qty: 250 },
  { _id: 4, item: 'leather boots', qty: 300 },
  { _id: 5, item: 'bow tie', qty: 180 }
]

A similar query written using the $unsetField alias returns the same results:

db.inventory.aggregate( [
   { $replaceWith:  {
        $unsetField: {
           field: "price.usd",
           input: "$$ROOT"
   } } }
] )

Remove Fields that Start with a Dollar Sign ($)

以下のドキュメントを持つinventoryコレクションを検討してください。

db.inventory.insertMany( [
   { _id: 1, item: 'sweatshirt', qty: 300, '$price': 45.99 },
   { _id: 2, item: 'winter coat', qty: 200, '$price': 499.99 },
   { _id: 3, item: 'sun dress', qty: 250, '$price': 199.99 },
   { _id: 4, item: 'leather boots', qty: 300, '$price': 249.99 },
   { _id: 5, item: 'bow tie', qty: 180, '$price': 9.99 }
} )

The following operation uses the $replaceWith pipeline stage, the $setField and $literal operators, and $$REMOVE to remove the "$price" field from each document:

db.inventory.aggregate( [
   { $replaceWith: {
        $setField: {
           field: { $literal: "$price" },
           input: "$$ROOT",
           value: "$$REMOVE"
   } } }
] )

この操作は次の結果を返します。

[
  { _id: 1, item: 'sweatshirt', qty: 300 },
  { _id: 2, item: 'winter coat', qty: 200 },
  { _id: 3, item: 'sun dress', qty: 250 },
  { _id: 4, item: 'leather boots', qty: 300 },
  { _id: 5, item: 'bow tie', qty: 180 }
]

A similar query written using the $unsetField alias returns the same results:

db.inventory.aggregate( [
  { $replaceWith: {
       $unsetField: {
          field: { $literal: "$price" },
          input: "$$ROOT"
  } } }
] )

以下も参照してください。

$unsetField

戻る

$setEquals

次へ

$setIntersection