I have a website I've created in Visual Studio 2008 and I need to take it live. How can I backup the database file to a .bak so I can hand it over to the hosting company to place on the server?
From a SQL prompt:
BACKUP DATABASE MyDatabase TO DISK='E:\MyDatabase.bak'
Go to Microsoft Server Management Studio and right click on your database name. Go to "Tasks" -> "Back Up..."
Then assign your properties, ensure that "Backup Type" is full.
Then at the right there is a button "Add" press that and set your filename, ensure that you place the extension .bak at the end of the file name.
Finally hit ok and wait for the backup to complete.
MSDN also has an article that explains this http://msdn.microsoft.com/en-us/library/ms187510.aspx
In ssms right click on the database, go to tasks, click back up. should be self explanatory from there.
You don't need a backup to do so (I assume you are using the AttachDbFilename model that Visual Studio uses by default). Just send them the mdf and tell them to attach it to their SQL server instance.
I assume you use SQL Server. This links will guide you:
How to: Back Up a Database (SQL Server Management Studio):
来源：https://stackoverflow.com/questions/883675/how-do-i-back-up-a-database-to-a-bak-file