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db.createCollection()
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Definition
db.
createCollection
( name, options )-
Changed in version 3.4: Added support for:
- Creation of views (see also
db.createView()
). - Collation.
Creates a new collection or view.
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, or to create a new collection that uses document validation.db.createCollection()
is a wrapper around the database commandcreate
.The
db.createCollection()
method has the following prototype form:db.createCollection(<name>, { capped: <boolean>, autoIndexId: <boolean>, size: <number>, max: <number>, storageEngine: <document>, validator: <document>, validationLevel: <string>, validationAction: <string>, indexOptionDefaults: <document>, viewOn: <string>, pipeline: <pipeline>, collation: <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, for preallocating space in a new collection, or for creating a view. The
options
document contains the following fields:Field Type Description capped
boolean Optional. To create a capped collection, specify true
. If you specifytrue
, you must also set a maximum size in thesize
field.autoIndexId
boolean Optional. Specify
false
to disable the automatic creation of an index on the_id
field.Important
For replica sets, do not set
autoIndexId
tofalse
.Deprecated since version 3.2.
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 thesize
limit before it reaches the maximum number of documents, MongoDB removes old documents. If you prefer to use themax
limit, ensure that thesize
limit, which is required for a capped collection, is sufficient to contain the maximum number of documents.usePowerOf2Sizes
boolean Optional. Available for the MMAPv1 storage engine only.
Deprecated since version 3.0: For the MMAPv1 storage engine, all collections use the power of 2 sizes allocation unless the
noPadding
option istrue
. TheusePowerOf2Sizes
option does not affect the allocation strategy.noPadding
boolean Optional. Available for the MMAPv1 storage engine only.
New in version 3.0:
noPadding
flag disables the power of 2 sizes allocation for the collection. WithnoPadding
flag set to true, the allocation strategy does not include additional space to accommodate document growth, as such, document growth will result in new allocation. Use for collections with workloads that are insert-only or in-place updates (such as incrementing counters).Defaults to
false
.Warning
Do not set
noPadding
if the workload includes removes or any updates that may cause documents to grow. For more information, see No Padding Allocation Strategy.storageEngine
document Optional. Available for the WiredTiger storage engine only.
New in version 3.0.
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.
validator
document Optional. Allows users to specify validation rules or expressions for the collection. For more information, see Schema Validation.
New in version 3.2.
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$geoNear
,$near
,$nearSphere
,$text
, and$where
.Note
- Validation occurs during updates and inserts. Existing documents do not undergo validation checks until modification.
- You cannot specify a validator for collections in the
admin
,local
, andconfig
databases. - You cannot specify a validator for
system.*
collections.
validationLevel
string Optional. Determines how strictly MongoDB applies the validation rules to existing documents during an update.
New in version 3.2.
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. validationAction
string Optional. Determines whether to
error
on invalid documents or justwarn
about the violations but allow invalid documents to be inserted.New in version 3.2.
Important
Validation of documents only applies to those documents as determined by the
validationLevel
.validationAction
Description "error"
Default Documents must pass validation before the write occurs. Otherwise, the write operation fails. "warn"
Documents do not have to pass validation. If the document fails validation, the write operation logs the validation failure. indexOptionDefaults
document Optional. Allows users to specify a default configuration for indexes when creating a collection.
The
indexOptionDefaults
option accepts astorageEngine
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.
New in version 3.2.
viewOn
string The name of the source collection or view from which to create the view. The name is not the full namespace of the collection or view; i.e. does not include the database name and implies the same database as the view to create. You must create views in the same database as the source collection.
See also
db.createView()
.New in version 3.4.
pipeline
array An array that consists of the aggregation pipeline stage.
db.createView
creates the view by applying the specifiedpipeline
to theviewOn
collection or view.The view definition is public; i.e.
db.getCollectionInfos()
andexplain
operations on the view will include the pipeline that defines the view. As such, avoid referring directly to sensitive fields and values in view definitions.See also
db.createView()
.New in version 3.4.
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.
New in version 3.4.
- Creation of views (see also
Access Control
If the deployment enforces authentication/authorization, db.createCollection()
requires the following privileges:
Required Privileges | |
---|---|
Create a non-capped collection |
|
Create a capped collection |