SQL Server allows you to create a table or an index on a filegroup that has no file assigned to it. Because there is no data file to hold anything, the table or the index thus created cannot be used. This may not be a problem because often you would probably use the table or the index 'immeidately', and would realize the problem. Well, you wouldn't be able to go anywhere. But there are cases, especially with an index, where the problem may not be discovered until some time later, and that could cause...(read more)