Attach DB error

In case of error try the following :

USE [master]
GO
CREATE DATABASE REAL_Warehouse_Sample_V6 ON
( FILENAME = N'D:\DB_MSSQL2012\REAL_Warehouse_Sample_V6.mdf' ),
( FILENAME = N'D:\DB_MSSQL2012\REAL_Warehouse_Sample_V6_log.LDF' )
FOR ATTACH
GO