Sql-server – Why can’t I use NEWSEQUENTIALID() as the default value for the column

In the SQL world, order is not an inherent property of a set of data. Thus, you get no guarantees from your RDBMS that your data will come back in a certain order -- or even in a consistent order -- unless you query your data with an ORDER BY clause.

From Craig Freedman:

Combining TOP with ORDER BY adds determinism to the set of rows returned. Without the ORDER BY, the set of rows returned depends on the query plan and may even vary from execution to execution.

Always use ORDER BY if you expect a well-defined and consistent order in your result set. Never rely on how your database may store the rows on disk (e.g. via a clustered index) to guarantee a certain ordering of data in your queries.

You can't attach a SQL Server 2008 R2 database to a SQL Server 2008 or 2005 instance. You can only go up, not down; you can't make your 2008 R2 database compatible with previous versions. The solution is to remove your Express instance and replace it with a 2008 R2 instance, then you will be able to attach your database...