diff --git a/DataStorage/DataMapperInterface.php b/DataStorage/DataMapperInterface.php
index 18ea21dcc..046ef7bc3 100644
--- a/DataStorage/DataMapperInterface.php
+++ b/DataStorage/DataMapperInterface.php
@@ -59,16 +59,6 @@ interface DataMapperInterface
      */
     public static function update($obj) : int;
 
-    /**
-     * Save data.
-     *
-     * @return void
-     *
-     * @since  1.0.0
-     * @author Dennis Eichhorn <d.eichhorn@oms.com>
-     */
-    public static function save();
-
     /**
      * Delete data.
      *
@@ -79,7 +69,7 @@ interface DataMapperInterface
      * @since  1.0.0
      * @author Dennis Eichhorn <d.eichhorn@oms.com>
      */
-    public static function delete($obj) : int;
+    public static function delete($obj);
 
     /**
      * Find data.
diff --git a/DataStorage/Database/DataMapperAbstract.php b/DataStorage/Database/DataMapperAbstract.php
index 1288269f1..1dbb12d07 100644
--- a/DataStorage/Database/DataMapperAbstract.php
+++ b/DataStorage/Database/DataMapperAbstract.php
@@ -1152,7 +1152,7 @@ class DataMapperAbstract implements DataMapperInterface
      * @since  1.0.0
      * @author Dennis Eichhorn <d.eichhorn@oms.com>
      */
-    public static function delete($obj, int $relations = RelationType::REFERENCE) /* : ?int */
+    public static function delete($obj, int $relations = RelationType::REFERENCE)
     {
         self::extend(__CLASS__);
         $reflectionClass = new \ReflectionClass(get_class($obj));