Attach mdf file to Database in SQL Server

Below is the code to attach *.mdf file to existing database:

USE [master]
GO
Method 1:
EXEC sp_attach_single_file_db @dbname='BISource',
@physname=N'C:\Users\mvaradhan\Downloads\AdventureWorksDW2008R2.mdf'
GO
Method 2:
CREATE DATABASE BISource ON
(FILENAME = N'C:\Users\mvaradhan\Downloads\AdventureWorksDW2008R2.mdf')
FOR ATTACH_REBUILD_LOG
GO
Method 3:
CREATE DATABASE BISource ON
( FILENAME = N'C:\Users\mvaradhan\Downloads\AdventureWorksDW2008R2.mdf')
FOR ATTACH
GO