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• Definition
• Behavior
• Examples
• Output

Definition

update

New in version 2.6.

The update command modifies documents in a collection. A single update command can contain multiple update statements. The update methods provided by the MongoDB drivers use this command internally.

The update command has the following syntax:

copy

{
   update: <collection>,
   updates: [
      { q: <query>, u: <update>, upsert: <boolean>, multi: <boolean>,
        collation: <document>, arrayFilters: <array> },
      { q: <query>, u: <update>, upsert: <boolean>, multi: <boolean>,
        collation: <document>, arrayFilters: <array> },
      { q: <query>, u: <update>, upsert: <boolean>, multi: <boolean>,
        collation: <document>, arrayFilters: <array> },
      ...
   ],
   ordered: <boolean>,
   writeConcern: { <write concern> },
   bypassDocumentValidation: <boolean>
}

The command takes the following fields:

Field	Type	Description
update	string	The name of the target collection.
updates	array	An array of one or more update statements to perform in the named collection.
ordered	boolean	Optional. If true, then when an update statement fails, return without performing the remaining update statements. If false, then when an update fails, continue with the remaining update statements, if any. Defaults to true.
writeConcern	document	Optional. A document expressing the write concern of the update command. Omit to use the default write concern.
bypassDocumentValidation	boolean	Optional. Enables update to bypass document validation during the operation. This lets you update documents that do not meet the validation requirements. New in version 3.2.

Each element of the updates array contains the following fields:

Field	Type	Description
q	document	The query that matches documents to update. Use the same query selectors as used in the find() method.
u	document	The modifications to apply. For details, see Behavior.
upsert	boolean	Optional. If true, perform an insert if no documents match the query. If both upsert and multi are true and no documents match the query, the update operation inserts only a single document.
multi	boolean	Optional. If true, updates all documents that meet the query criteria. If false, limit the update to one document that meet the query criteria. Defaults to false.
collation	document	Optional. Specifies the collation to use for the operation. Collation allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks. The collation option has the following syntax: copy collation: { locale: <string>, caseLevel: <boolean>, caseFirst: <string>, strength: <int>, numericOrdering: <boolean>, alternate: <string>, maxVariable: <string>, backwards: <boolean> } When specifying collation, the locale field is mandatory; all other collation fields are optional. For descriptions of the fields, see Collation Document. If the collation is unspecified but the collection has a default collation (see db.createCollection()), the operation uses the collation specified for the collection. If no collation is specified for the collection or for the operations, MongoDB uses the simple binary comparison used in prior versions for string comparisons. You cannot specify multiple collations for an operation. For example, you cannot specify different collations per field, or if performing a find with a sort, you cannot use one collation for the find and another for the sort. New in version 3.4.
arrayFilters	array	Optional. An array of filter documents that determines which array elements to modify for an update operation on an array field. In the update document, use the $[<identifier>] filtered positional operator to define an identifier, which you then reference in the array filter documents. You cannot have an array filter document for an identifier if the identifier is not included in the update document. Note The <identifier> must begin with a lowercase letter and contain only alphanumeric characters. You can include the same identifier multiple times in the update document; however, for each distinct identifier ($[identifier]) in the update document, you must specify exactly one corresponding array filter document. That is, you cannot specify multiple array filter documents for the same identifier. For example, if the update statement includes the identifier x (possibly multiple times), you cannot specify the following for arrayFilters that includes 2 separate filter documents for x: copy [ { "x.a": { $gt: 85 } }, { "x.b": { $gt: 80 } } ] However, you can specify compound conditions on the same identifier in a single filter document, such as in the following examples: copy [ { $or: [{"x.a": {$gt: 85}}, {"x.b": {$gt: 80}}] } ] [ { $and: [{"x.a": {$gt: 85}}, {"x.b": {$gt: 80}}] } ] [ { "x.a": { $gt: 85 }, "x.b": { $gt: 80 } } ] For examples, see Specify arrayFilters for Array Update Operations. New in version 3.6.

Returns:	A document that contains the status of the operation. See Output for details.

Behavior

The <update> document can contain either all update operator expressions or all field:value expressions.

{
  $set: { status: "D" },
  $inc: { quantity: 2 }
}

{
  status: "D",
  quantity: 4
}

Examples

db.runCommand(
   {
      update: "users",
      updates: [
         {
           q: { user: "abc123" }, u: { $set: { status: "A" }, $inc: { points: 1 } }
         }
      ],
      ordered: false,
      writeConcern: { w: "majority", wtimeout: 5000 }
   }
)

{ "ok" : 1, "nModified" : 1, "n" : 1 }