diff --git a/PhpRbac/src/PhpRbac/Rbac.php b/PhpRbac/src/PhpRbac/Rbac.php
index c39134c..b79571f 100644
--- a/PhpRbac/src/PhpRbac/Rbac.php
+++ b/PhpRbac/src/PhpRbac/Rbac.php
@@ -19,12 +19,12 @@ public function __construct($config = '')
         if ((string)$config === 'unit_test') {
             require_once dirname(dirname(__DIR__)) . '/tests/database/database.config';
         } else {
-            $adapter = $config['adapter'] ?: "pdo_sqlite";
-            $host = $config['host'] ?: "localhost";
-            $user = $config['user'] ?: "root";
-            $pass = $config['pass'] ?: "";
-            $tablePrefix = $config['prefix'] ?: "phprbac_";
-            $dbname =  $config['db_name'] ?: false;
+            $adapter = isset($config['adapter']) ? $config['adapter'] : "pdo_sqlite";
+            $host = isset($config['host']) ? $config['host'] : "localhost";
+            $user = isset($config['user']) ? $config['user'] : "root";
+            $pass = isset($config['pass']) ? $config['pass'] : "";
+            $tablePrefix = isset($config['prefix']) ? $config['prefix'] : "phprbac_";
+            $dbname =  isset($config['db_name']) ? $config['db_name'] : false;
 
             if(!$dbname){
                 throw new ConfigurationException("db_name",$config['db_name']);