No doubt that as compare to previous version the current SQL Server 2005 provides more new language constructs and primitives for the T-SQL language than can be utilized. Still there are many out there not entirely ready to upgrade from SQL Server 2000 to 2005. In this case you can take few advantages of SQL 2005 by keeping the user databases in SQL 2000 (80) mode. As explained SQL Server 2005 has a "compatibility mode" that you can set "back" to 8.0 (SQL Server 2000). By intiating this feature it...(
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Read the complete post at http://sqlserver-qa.net/blogs/tools/archive/2007/08/30/setting-database-compatibility-to-sql-2000-on-a-sql-server-2005-instance.aspx