diff --git a/config-templates/config.php b/config-templates/config.php
index 3104e467218cdc73f16e5370a93d4d47867a504e..418504084d3ff6433e92aa1c8957e3c70b6fa9b2 100644
--- a/config-templates/config.php
+++ b/config-templates/config.php
@@ -571,6 +571,15 @@ $config = array(
      * - 'cachelength': Maximum time metadata cah be cached, in seconds. Default to 24
      *                  hours (86400 seconds). Optional.
      *
+     * PDO metadata handler:
+     * This metadata handler looks up for the metadata of an entity stored in a database.
+     * The PDO metadata handler defines the following options:
+     * - 'type': This is always 'pdo'.
+     * - 'dsn': The database connection string. Mandatory.
+     * - 'username': Database username
+     * - 'cachedir': Database password
+     * - 'usePersistentConnection': Enable/Disable persistent database connection. Default is false.
+     *
      *
      * Examples:
      *
@@ -593,6 +602,11 @@ $config = array(
      *     array('type' => 'mdx', server => 'http://mdx.server.com:8080', 'cachedir' => '/var/simplesamlphp/mdx-cache', 'cachelength' => 86400)
      *     ),
      *
+     * This example defines an pdo source.
+     * 'metadata.sources' => array(
+     *     array('type' => 'pdo', server => 'mysql:host=localhost;dbname=saml', 'username' => 'simplesamlphp', 'password' => 'SuperSecretPassword')
+     *     ),
+     *
      * Default:
      * 'metadata.sources' => array(
      *     array('type' => 'flatfile')