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MongoDB\Database::createCollection()

Definition

MongoDB\Database::createCollection

Explicitly creates a collection.

function createCollection($collectionName, array $options = []): array|object

MongoDB creates collections implicitly when you first reference the collection in a command, such as when inserting a document into a new collection. You may also explicitly create a collection with specific options using the MongoDB\Database::createCollection() method, or using db.createCollection() in the mongo shell.

Explicitly creating collections enables you to create capped collections, specify document validation criteria, or configure your storage engine or indexing options.

This method has the following parameters:

Parameter Type Description
$collectionName string The name of the collection to create.
$options array Optional. An array specifying the desired options.

The $options parameter supports the following options:

Option Type Description
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 to false.

Deprecated since version 1.4: This option has been deprecated since MongoDB 3.2. As of MongoDB 4.0, this option cannot be false when creating a replicated collection (i.e. a collection outside of the local database in any mongod mode).

capped boolean Optional. To create a capped collection, specify true. If you specify true, you must also set a maximum size in the size option.
collation array|object

Optional. Specifies the collation for the collection.

Collation allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks. When specifying collation, the locale field is mandatory; all other collation fields are optional. For descriptions of the fields, see Collation Document.

This option is available in MongoDB 3.4+ and will result in an exception at execution time if specified for an older server version.

flags integer

Optional. Available for the MMAPv1 storage engine only to set the usePowerOf2Sizes and noPadding flags.

The MongoDB PHP Library provides constants that you can combine with a bitwise OR operator to set the flag values:

  • MongoDB\Operation\CreateCollection::USE_POWER_OF_2_SIZES: 1
  • MongoDB\Operation\CreateCollection::NO_PADDING: 2

Defaults to 1.

Note

MongoDB 3.0 and later ignores the usePowerOf2Sizes flag. See collMod and db.createCollection() for more information.

indexOptionDefaults array|object

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 configurations specified when creating indexes are validated and logged to the oplog during replication to support replica sets with members that use different storage engines.

max integer Optional. The maximum number of documents allowed in the capped collection. The size option 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.
maxTimeMS integer Optional. The cumulative time limit in milliseconds for processing operations on the cursor. MongoDB aborts the operation at the earliest following interrupt point.
session MongoDB\Driver\Session

Optional. Client session to associate with the operation.

Sessions are not supported for server versions prior to 3.6.

New in version 1.3.

size integer 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 option is required for capped collections and ignored for other collections.
storageEngine array|object

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 configurations specified when creating collections are validated and logged to the oplog during replication to support replica sets with members that use different storage engines.

typeMap array

Optional. The type map to apply to cursors, which determines how BSON documents are converted to PHP values. Defaults to the database’s type map.

This will be used for the returned command result document.

validator array

Optional. Allows users to specify validation rules or expressions for the collection. For more information, see Document Validation in the MongoDB manual.

The validator option takes an array that specifies the validation rules or expressions. You can specify the expressions using the same operators as MongoDB’s 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, and config databases.
  • You cannot specify a validator for system.* collections.
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.

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.
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.
writeConcern MongoDB\Driver\WriteConcern

Optional. Write concern to use for the operation. Defaults to the database’s write concern.

This is not supported for server versions prior to 3.4 and will result in an exception at execution time if used.

Note that not all options are available on all versions of MongoDB. Document validation, for example, was added in MongoDB 3.2; similarly, the WiredTiger storage engine is available only for MongoDB 3.0 and later. Refer to the create command reference in the MongoDB manual for compatibility considerations.

Return Values

An array or object with the result document of the create command.

Errors/Exceptions

MongoDB\Exception\UnsupportedException if options are used and not supported by the selected server (e.g. collation, readConcern, writeConcern).

MongoDB\Exception\InvalidArgumentException for errors related to the parsing of parameters or options.

MongoDB\Driver\Exception\RuntimeException for other errors at the driver level (e.g. connection errors).

Example

The following example creates a users collection in the test database with document validation criteria:

<?php

$db = (new MongoDB\Client)->test;

$result = $db->createCollection('users', [
    'validator' => [
        'username' => ['$type' => 'string'],
        'email' => ['$regex' => '@mongodb\.com$'],
    ],
]);

var_dump($result);

The output would then resemble:

object(MongoDB\Model\BSONDocument)#11 (1) {
  ["storage":"ArrayObject":private]=>
  array(1) {
    ["ok"]=>
    float(1)
  }
}

See Also