diff --git a/lib/Cake/Model/Datasource/DboSource.php b/lib/Cake/Model/Datasource/DboSource.php
index 75a18dcf407..04cd13247a1 100644
--- a/lib/Cake/Model/Datasource/DboSource.php
+++ b/lib/Cake/Model/Datasource/DboSource.php
@@ -1562,6 +1562,7 @@ protected function _mergeAssociation(&$data, &$merge, $association, $type, $self
 					}
 				} else {
 					if (is_array($merge[0][$association])) {
+						$mergeAssocTmp = array();
 						foreach ($dataAssociation as $k => $v) {
 							if (!is_array($v)) {
 								$dataAssocTmp[$k] = $v;
@@ -3586,4 +3587,4 @@ public function __destruct() {
 		parent::__destruct();
 	}
 
-}
\ No newline at end of file
+}