===============================
MongoDB\\Client::startSession()
===============================

.. versionadded:: 1.3

.. default-domain:: mongodb

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Definition
----------

.. phpmethod:: MongoDB\\Client::startSession()

   Start a new client session for use with this client.

   .. code-block:: php

      function startSession(array $options = []): MongoDB\Driver\Session

   Refer to the :php:`MongoDB\\Driver\\Manager::startSession()
   <mongodb-driver-manager.startsession>` extension reference for accepted
   options.

Return Values
-------------

A :php:`MongoDB\Driver\Session <mongodb-driver-session>` object.

Errors/Exceptions
-----------------

.. include:: /includes/extracts/error-driver-invalidargumentexception.rst
.. include:: /includes/extracts/error-driver-runtimeexception.rst

Example
-------

The following example starts a new session:

.. code-block:: php

   <?php

   $client = new MongoDB\Client;

   $session = $client->startSession();

   var_dump($session);

The output would then resemble::

   object(MongoDB\Driver\Session)#2043 (4) {
     ["logicalSessionId"]=>
     array(1) {
       ["id"]=>
       object(MongoDB\BSON\Binary)#225 (2) {
         ["data"]=>
         string(16) "................"
         ["type"]=>
         int(4)
       }
     }
     ["clusterTime"]=>
     NULL
     ["causalConsistency"]=>
     bool(true)
     ["operationTime"]=>
     NULL
   }

See Also
--------

- :php:`MongoDB\\Driver\\Manager::startSession()
  <manual/en/mongodb-driver-manager.startsession.php>`
- :ref:`Causal Consistency <causal-consistency>` in the MongoDB manual