DB Snapshot

A database snapshot is a read-only, static view of a database, called the source database. In Microsoft SQL Server 2005, you use SQL Server 2005 statements for creating, reverting to, and deleting a database snapshot. However, you can use SQL Server Management Studio to view existing database snapshots.

Example
CREATE DATABASE DAT_SS ON
( NAME = DAT, FILENAME =
'C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Data\DAT_SS.ss' )
AS SNAPSHOT OF DAT;