diff --git a/DataStorage/Database/DataMapperAbstract.php b/DataStorage/Database/DataMapperAbstract.php
index c33b4223e..49de1d310 100644
--- a/DataStorage/Database/DataMapperAbstract.php
+++ b/DataStorage/Database/DataMapperAbstract.php
@@ -678,7 +678,7 @@ class DataMapperAbstract implements DataMapperInterface
      *
      * @since 1.0.0
      */
-    private static function getObjectId(object $obj, \ReflectionClass $refClass = null)
+    public static function getObjectId(object $obj, \ReflectionClass $refClass = null)
     {
         $refClass = $refClass ?? new \ReflectionClass($obj);
         $refProp  = $refClass->getProperty(static::$columns[static::$primaryField]['internal']);
@@ -1007,7 +1007,7 @@ class DataMapperAbstract implements DataMapperInterface
      * In case of a many to many relation the relation has to be stored in a relation table
      *
      * @param string $propertyName Property name to initialize
-     * @param array  $objsIds      Object ids to insert
+     * @param array  $objsIds      Object ids to insert (can also be the object itself)
      * @param mixed  $objId        Model to reference
      *
      * @return void
@@ -1024,6 +1024,11 @@ class DataMapperAbstract implements DataMapperInterface
                 ->insert(static::$hasMany[$propertyName]['src'], static::$hasMany[$propertyName]['dst']);
 
             foreach ($objsIds as $key => $src) {
+                if (\is_object($src)) {
+                    $mapper = \get_class($src) . 'Mapper';
+                    $src    = $mapper::getObjectId($src);
+                }
+
                 $relQuery->values($src, $objId);
             }
 
diff --git a/Message/Http/Request.php b/Message/Http/Request.php
index 9d9920c9d..0cfc80691 100644
--- a/Message/Http/Request.php
+++ b/Message/Http/Request.php
@@ -169,7 +169,7 @@ final class Request extends RequestAbstract
             \parse_str($content, $temp);
             $this->data += $temp;
         } elseif (\stripos($_SERVER['CONTENT_TYPE'], 'multipart/form-data') !== false) {
-            $content = file_get_contents('php://input');
+            $content = \file_get_contents('php://input');
             $stream   = \fopen('php://input', 'r');
             $partInfo = null;
             $boundary = null;