A new Developer within our testing environment asked me this question to see whether they can use DETACH/ATTACH method than using ALTER database method. For the user databases it is available such method of DETACH/ATTACH method when moving the databases, but for system database it is not possible as they are in exclusive use for sqlserve.exe file. As by default configuration you will not be able to use detach/attach method for system databases. For more information about how to move system databases...(
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Read the complete post at http://sqlserver-qa.net/blogs/tools/archive/2007/08/27/move-tempdb-and-don-t-want-to-use-detach-method.aspx