db.createCollection()

Definition

db.createCollection(name, options)

Creates a new collection. For views, see db.createView().

Because MongoDB creates a collection implicitly when the collection is first referenced in a command, this method is used primarily for creating new collections that use specific options. For example, you use db.createCollection() to create a:

• Capped collection.

• Clustered collection.

• New collection that uses document validation.

db.createCollection() is a wrapper around the database command create.

The db.createCollection() method has the following prototype form:

db.createCollection( <name>,
   {
     capped: <boolean>,
     timeseries: {                  // Added in MongoDB 5.0
        timeField: <string>,        // required for time series collections
        metaField: <string>,
        granularity: <string>,
        bucketMaxSpanSeconds: <number>,  // Added in MongoDB 6.3
        bucketRoundingSeconds: <number>  // Added in MongoDB 6.3
     },
     expireAfterSeconds: <number>,
     clusteredIndex: <document>,  // Added in MongoDB 5.3
     changeStreamPreAndPostImages: <document>,  // Added in MongoDB 6.0
     size: <number>,
     max: <number>,
     storageEngine: <document>,
     validator: <document>,
     validationLevel: <string>,
     validationAction: <string>,
     indexOptionDefaults: <document>,
     viewOn: <string>,
     pipeline: <pipeline>,
     collation: <document>,
     writeConcern: <document>
   }
)

The db.createCollection() method has the following parameters:

Parameter	Type	Description
name	string	The name of the collection to create. See Naming Restrictions.
options	document	Optional. Configuration options for creating a: Capped collection Clustered collection View

The options document contains the following fields:

Field	Type	Description
capped	boolean	Optional. To create a capped collection, specify true. If you specify true, you must also set a maximum size in the size field.
timeseries.timeField	string	Required when creating a time series collection. The name of the field which contains the date in each time series document. Documents in a time series collection must have a valid BSON date as the value for the timeField.
timeseries.metaField	string	Optional. The name of the field which contains metadata in each time series document. The metadata in the specified field should be data that is used to label a unique series of documents. The metadata should rarely, if ever, change. The name of the specified field may not be _id or the same as the timeseries.timeField. The field can be of any type except array.
timeseries.granularity	integer	Optional. Do not use if setting bucketRoundingSeconds and bucketMaxSpanSeconds. Possible values are seconds (default), minutes, and hours. Set granularity to the value that most closely matches the time between consecutive incoming timestamps. This improves performance by optimizing how MongoDB internally stores data in the collection. For more information on granularity and bucket intervals, see Set Granularity for Time Series Data.
timeseries.bucketMaxSpanSeconds	integer	Optional. Use with bucketRoundingSeconds as an alternative to granularity. Sets the maximum time between timestamps in the same bucket. Possible values are 1-31536000. New in version 6.3.
timeseries.bucketRoundingSeconds	integer	Optional. Use with bucketMaxSpanSeconds as an alternative to granularity. Must be equal to bucketMaxSpanSeconds. When a document requires a new bucket, MongoDB rounds down the document's timestamp value by this interval to set the minimum time for the bucket. For example, setting both parameters to 1800 rounds new buckets down to the nearest 30 minutes. If a document with a time of 2023-03-27T18:24:35Z does not fit an existing bucket, MongoDB creates a new bucket with a minimum time of 2023-03-27T18:00:00Z and a maximum time of 2023-03-27T18:29:59Z. New in version 6.3.
expireAfterSeconds	number	Optional. Specifies the seconds after which documents in a time series collection or clustered collection expire. MongoDB deletes expired documents automatically. For clustered collections, the documents are deleted automatically based on the clustered index key _id and the values must be date types. See TTL Indexes.
clusteredIndex	document	Starting in MongoDB 5.3, you can create a collection with a clustered index. Collections created with a clustered index are called clustered collections. See Clustered Collections. clusteredIndex has the following syntax: clusteredIndex: { key: { <string> }, unique: <boolean>, name: <string> } Field Description key Required. The clustered index key field. Must be set to { _id: 1 }. The default value for the _id field is an automatically generated unique object identifier, but you can set your own clustered index key values. unique Required. Must be set to true. A unique index indicates the collection will not accept inserted or updated documents where the clustered index key value matches an existing value in the index. name Optional. A name that uniquely identifies the clustered index. New in version 5.3.
changeStreamPreAndPostImages	document	Optional. Starting in MongoDB 6.0, you can use change stream events to output the version of a document before and after changes (the document pre- and post-images): The pre-image is the document before it was replaced, updated, or deleted. There is no pre-image for an inserted document. The post-image is the document after it was inserted, replaced, or updated. There is no post-image for a deleted document. Enable changeStreamPreAndPostImages for a collection using db.createCollection(), create, or collMod. changeStreamPreAndPostImages has the following syntax: changeStreamPreAndPostImages: { enabled: <boolean> } enabled Description true Enables change stream pre- and post-images for a collection. false Disables change stream pre- and post-images for a collection. For complete examples with the change stream output, see Change Streams with Document Pre- and Post-Images. For a db.createCollection() example on this page, see Create a Collection with Change Stream Pre- and Post-Images for Documents. New in version 6.0.
size	number	Optional. Specify a maximum size in bytes for a capped collection. Once a capped collection reaches its maximum size, MongoDB removes the older documents to make space for the new documents. The size field is required for capped collections and ignored for other collections.
max	number	Optional. The maximum number of documents allowed in the capped collection. The size limit takes precedence over this limit. If a capped collection reaches the size limit before it reaches the maximum number of documents, MongoDB removes old documents. If you prefer to use the max limit, ensure that the size limit, which is required for a capped collection, is sufficient to contain the maximum number of documents.
storageEngine	document	Optional. Available for the WiredTiger storage engine only. Allows users to specify configuration to the storage engine on a per-collection basis when creating a collection. The value of the storageEngine option should take the following form: { <storage-engine-name>: <options> } Storage engine configuration specified when creating collections are validated and logged to the oplog during replication to support replica sets with members that use different storage engines. Tip See also: Specify Storage Engine Options
validator	document	Optional. Allows users to specify validation rules or expressions for the collection. The validator option takes a document that specifies the validation rules or expressions. You can specify the expressions using the same operators as the query operators with the exception of $near, $nearSphere, $text, and $where. To learn how to create a collection with schema validation, see Specify JSON Schema Validation.
validationLevel	string	Optional. Determines how strictly MongoDB applies the validation rules to existing documents during an update. validationLevel Description "off" No validation for inserts or updates. "strict" Default Apply validation rules to all inserts and all updates. "moderate" Apply validation rules to inserts and to updates on existing valid documents. Do not apply rules to updates on existing invalid documents. To see an example that uses validationLevel, see Specify Validation Level for Existing Documents.
validationAction	string	Optional. Determines whether to error on invalid documents or just warn about the violations but allow invalid documents to be inserted. Important Validation of documents only applies to those documents as determined by the validationLevel. To see an example that uses validationAction, see Choose How to Handle Invalid Documents.
indexOptionDefaults	document	Optional. Allows users to specify a default configuration for indexes when creating a collection. The indexOptionDefaults option accepts a storageEngine document, which should take the following form: { <storage-engine-name>: <options> } Storage engine configuration specified when creating indexes are validated and logged to the oplog during replication to support replica sets with members that use different storage engines.
viewOn	string	The name of the source collection or view from which to create a view. For details, see db.createView().
pipeline	array	An array that consists of the aggregation pipeline stage(s). db.createView() creates a view by applying the specified pipeline to the viewOn collection or view. For details, see db.createView().
collation	document	Specifies the default collation for the collection. 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: 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 you specify a collation at the collection level: Indexes on that collection will be created with that collation unless the index creation operation explicitly specify a different collation. Operations on that collection use the collection's default collation unless they explicitly specify a different collation. 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. 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. For a collection, you can only specify the collation during the collection creation. Once set, you cannot modify the collection's default collation. For an example, see Specify Collation.
writeConcern	document	Optional. A document that expresses the write concern for the operation. Omit to use the default write concern. When issued on a sharded cluster, mongos converts the write concern of the create command and its helper db.createCollection() to "majority".

Access Control

If the deployment enforces authentication/authorization, db.createCollection() requires the following privileges:

A user with the readWrite built in role on the database has the required privileges to run the listed operations. Either create a user with the required role or grant the role to an existing user.

Behavior

Examples

db.createCollection("log", { capped : true, size : 5242880, max : 5000 } )

db.createCollection(
    "weather24h",
    {
       timeseries: {
          timeField: "timestamp",
          metaField: "data",
          granularity: "hours"
       },
       expireAfterSeconds: 86400
    }
)

db.createCollection(
    "weather24h",
    {
       timeseries: {
          timeField: "timestamp",
          metaField: "data",
          bucketMaxSpanSeconds: "3600",
          bucketRoundingSeconds: "3600"
       },
       expireAfterSeconds: 86400
    }
)

db.createCollection(
   "stocks",
   { clusteredIndex: { "key": { _id: 1 }, "unique": true, "name": "stocks clustered key" } }
)

db.createCollection(
   "temperatureSensor",
   { changeStreamPreAndPostImages: { enabled: true } }
);

db.createCollection( "myColl", { collation: { locale: "fr" } } );

{ _id: 1, category: "café" }
{ _id: 2, category: "cafe" }
{ _id: 3, category: "cafE" }

db.myColl.find().sort( { category: 1 } )

{ "_id" : 2, "category" : "cafe" }
{ "_id" : 3, "category" : "cafE" }
{ "_id" : 1, "category" : "café" }

{ "_id" : 3, "category" : "cafE" }
{ "_id" : 2, "category" : "cafe" }
{ "_id" : 1, "category" : "café" }

db.createCollection(
   "users",
   { storageEngine: { wiredTiger: { configString: "<option>=<setting>" } } }
)