DQL custom functions on doctrine reference page

Seems that there is two possibilities to configure custom DQL functions

It should be clearified in doctrine reference page because It may confuse some people if they just read the cookbook: http://symfony.com/doc/current/cookbook/doctrine/custom_dql_functions.html

reference/configuration/doctrine.rst

@@ -411,3 +411,42 @@ Each connection is also accessible via the ``doctrine.dbal.[name]_connection``
 service where ``[name]`` is the name of the connection.
 
 .. _DBAL documentation: http://docs.doctrine-project.org/projects/doctrine-dbal/en/latest/reference/configuration.html
+
+Register Custom DQL Functions
+-----------------------------
+
+Doctrine allows you to specify custom DQL functions. For more information
+on this topic, read Doctrine's cookbook article "`DQL User Defined Functions`_".
+
+In Symfony, you can register your custom DQL functions as follows:
+
+.. code-block:: yaml
+    doctrine:
+        orm:
+            # ...
+            entity_managers:
+                default:
+                    # ...
+                    dql:
+                        string_functions:
+                            test_string: Acme\HelloBundle\DQL\StringFunction
+                            second_string: Acme\HelloBundle\DQL\SecondStringFunction
+                        numeric_functions:
+                            test_numeric: Acme\HelloBundle\DQL\NumericFunction
+                        datetime_functions:
+                            test_datetime: Acme\HelloBundle\DQL\DatetimeFunction
+
+However, if you are only using one entity manager, DQL functions can be registed like this:
+
+.. code-block:: yaml
+    doctrine:
+        orm:
+            # ...
+            dql:
+                string_functions:
+                    test_string: Acme\HelloBundle\DQL\StringFunction
+                    second_string: Acme\HelloBundle\DQL\SecondStringFunction
+                numeric_functions:
+                    test_numeric: Acme\HelloBundle\DQL\NumericFunction
+                datetime_functions:
+                    test_datetime: Acme\HelloBundle\DQL\DatetimeFunction