A system stored procedure is a proc that is stored in the master database that you can run in the context of other databases on the instance. For example, sp_msforeachtable is an example of a system stored procedure. You can run this procedure in any database on the instance and it will loop through the tables in the database and issue a command against each. As an example, here is a stored procedure I wrote when SQL Server 2005 first came out. This procedure uses a dynamic management view to recurse...