Database Detach offline

Database separation:
Generally by default, the database in the online state we can not do any copy deletion of database files, and so on, if the database is separated, the data files can be copied, cut, delete and other operations. Generally want to directly back up data files, the first separation of the database, and then copy the data file to another place, and then attach the data file back to it.
Database offline:
Some important data for security will choose offline processing, when needed to use and then go online!!!

Detaching and offline can make the database no longer available, but it needs to be attached before it can be used, and is available only when you are offline

If you do not succeed, you need to stop SQL Server services.

Database Detach offline