diff --git a/src/Schema/Wrapper.php b/src/Schema/Wrapper.php
index f73e6fd..f4a5d74 100755
--- a/src/Schema/Wrapper.php
+++ b/src/Schema/Wrapper.php
@@ -77,7 +77,8 @@ class Wrapper{
 
     public static function exec($sql){
         $instance = self::getInstance();
-        $sql = preg_replace('/{(.*)}/', "$con->prefix$1", $sql);
+        $prefix = $instance->_adapter->getConnection()->prefix;
+        $sql = preg_replace('/{(.*)}/', "$prefix$1", $sql);
         $instance->_driver->exec($sql);
     }