Sql-server – How to guarantee data is the same after upgrading SQL Server

Have you tried with backup and restore? Make a backup in SQL Server 2005 and use it to restore the db to the R2 instance. At the end of the restore it should be upgraded automatically.

Or is it any different for SBS 2003 and can't make a backup?

To be able to transfer also the logins you could get help from the following KB articles:

• How to transfer logins and passwords between instances of SQL Server and
• How to transfer the logins and the passwords between instances of SQL Server 2005 and SQL Server 2008.

PS: posted initially as comment because I never saw a SBS close enough :-).

If you don't:

• it will be unmaintainable at some point because of OS, version, patch, whatever
• hardware failure may force an upgrade at the wrong time

What you gain:

• older code can be simplified with new constructs (eg ROW_NUMBER)
• far better error handling (TRY/CATCH)
• engine improvements: most queries will run quicker on a later version

MS don't support it anymore either