What is the purpose of registering a DB in SQL? I am trying to go through the Management Studio Express tutorial with SQL Server 2005 express SP2. I figured out how to install and attach the AdventureWorksDB to my instance of SQL Server but I don't see what the importance of registering the AdventureWorksDB, since it is already listed as a DB within my instance why do it?

Also, a more general question, when actually coding SQL for a SQL server DB does Manegement Studio provide a coding app or do most people use Visual Studio or something. I'm referencing a T-SQL book that mentions query analyzer which is supposedly built in to the SQL Server Management Studio?
Thanks!

When you attach a database to SQL Server, you are telling the server to use a particular database that you've added as a file. When you Register a server, you are telling your SSMS (Management Studio Express) on your PC about the server. S

SMS is a combination of the old Enterprise Manager and Query Analyser.  When you open a new query, you are staring at something that looks very like the old Query analyser.