db.collection.createIndex() (mongosh method)

keys

document

A document that contains the field and value pairs where the field is the index key and the value describes the type of index for that field.

For an ascending index on a field, specify a value of 1. For descending index, specify a value of -1.

An asterisk (*) is not a valid index name.

MongoDB supports several different index types, including:

• text

• geospatial

• hashed indexes

See index types for more information.

Wildcard indexes support workloads where users query against custom fields or a large variety of fields in a collection.

• You can create a wildcard index on a specific field and its subpaths or on all of the fields in a document.

  For details, see Wildcard Indexes.

options

document

Optional. A document that contains a set of options that controls the creation of the index. See Options for details.

commitQuorum

integer or string

Optional. The minimum number of data-bearing voting replica set members (i.e. commit quorum), including the primary, that must report a successful index build before the primary marks the indexes as ready. A "voting" member is any replica set member where members[n].votes is greater than 0.

Supports the following values:

• "votingMembers" - all data-bearing voting replica set members (Default).

• "majority" - a simple majority of data-bearing voting replica set members.

• <int> - a specific number of data-bearing voting replica set members.

• 0 - Disables quorum-voting behavior. Members start the index build simultaneously but do not vote or wait for quorum before completing the index build. If you start an index build with a commit quorum of 0, you cannot later modify the commit quorum using setIndexCommitQuorum.

• A replica set tag name.

collation

document

Optional. Specifies the collation for the index.

Collation allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks.

If you have specified a collation at the collection level, then:

• If you do not specify a collation when creating the index, MongoDB creates the index with the collection's default collation.

• If you do specify a collation when creating the index, MongoDB creates the index with the specified collation.

The collation option has the following syntax:

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.

weights

document

Optional. For text indexes, a document that contains field and weight pairs. The weight is an integer ranging from 1 to 99,999 and denotes the significance of the field relative to the other indexed fields in terms of the score. You can specify weights for some or all the indexed fields. See Assign Weights to Text Search Results on Self-Managed Deployments to adjust the scores. The default value is 1.

Starting in MongoDB 5.0, the weights option is only allowed for text indexes.

default_language

string

Optional. For text indexes, the language that determines the list of stop words and the rules for the stemmer and tokenizer. See Text Search Languages on Self-Managed Deployments for the available languages and Specify Language for Text Indexes on Self-Managed MongoDB for more information and examples. The default value is english.

language_override

string

Optional. For text indexes, the name of the field, in the collection's documents, that contains the override language for the document. The default value is language. See Specify Language for Text Indexes on Self-Managed MongoDB for an example.

textIndexVersion

integer

Optional. The text index version number. Users can use this option to override the default version number.

For available versions, see Text Index Versions on Self-Managed Deployments.

2dsphereIndexVersion

integer

Optional. The 2dsphere index version number. Users can use this option to override the default version number.

For the available versions, see 2dsphere Indexes.

bits

integer

Optional. For 2d indexes, the number of precision of the stored geohash value of the location data.

The bits value ranges from 1 to 32 inclusive. The default value is 26.

min

number

Optional. For 2d indexes, the lower inclusive boundary for the longitude and latitude values. The default value is -180.0.

max

number

Optional. For 2d indexes, the upper inclusive boundary for the longitude and latitude values. The default value is 180.0.

wildcardProjection

document

Optional. Allows users to include or exclude specific field paths from a wildcard index.

This option is only valid when you create a wildcard index on all document fields. You cannot specify the wildcardProjection option when you create a wildcard index on a specific field path and its subfields.

wildcardProjection works with specifications like:

{ "$**": 1 }
{ "userID":, "$**": 1 }

However, you can't define an index that includes the same field in the wildcard fields and the regular (non-wildcard) fields. To define the index correctly, use a wildcardProjection to exclude duplicated fields from the wildcard pattern.

wildcardProjection does not work with a specification like:

 ``{ "path.to.field.$**" : 1 }``

The wildcardProjection option takes the following form:

wildcardProjection: {
  "path.to.field.a" : <value>,
  "path.to.field.b" : <value>
}

The <value> can be either of the following:

• 1 or true to include the field in the wildcard index.

• 0 or false to exclude the field from the wildcard index.