#19052585 : fixed the problem that default value is not set when it is 0

git-svn-id: http://xe-core.googlecode.com/svn/sandbox@7622 201d5d3c-b55e-5fd7-737f-ddc643e51545

classes/db/DBMssql.class.php

@@ -370,7 +370,7 @@
                     $this->column_type[$type],
                     !in_array($type,array('number','text'))&&$size?'('.$size.')':'',
                     $primary_key?'primary key':'',
-                    $default?"default '".$default."'":'',
+                    isset($default)?"default '".$default."'":'',
                     $notnull?'not null':'null',
                     $auto_increment?'identity(1,1)':''
                     );