=====================================
MongoDB\\Database::createCollection()
=====================================

.. default-domain:: mongodb

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Definition
----------

.. phpmethod:: MongoDB\\Database::createCollection

   Explicitly creates a collection.
   
   .. code-block:: php

      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 ``createCollection()``
   method, or using :dbcommand:`create` in the :program:`mongo` shell.
   
   Explicitly creating collections enables you to create
   :manual:`capped collections </core/capped-collections>`, specify
   :manual:`document validation criteria </core/document-validation>`,
   or configure your storage engine or indexing options.
   
   :phpmethod:`MongoDB\\Database::createCollection` has the following
   parameters:
   
   .. include:: /includes/apiargs/MongoDBDatabase-method-createCollection-param.rst
   
   The ``$options`` parameter accepts the following options:
   
   .. include:: /includes/apiargs/MongoDBDatabase-method-createCollection-option.rst
   
   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 :manual:`create command
   </reference/command/create>` reference in the MongoDB manual for
   compatibility considerations.

Output
------

Returns the command result document as an array.

Example
-------

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

.. code-block:: php

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

   $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)
     }
   }

.. seealso::

   :manual:`create </reference/command/create>` command reference in
   the MongoDB manual