System Databases

When you install SQL Server several databases are created automatically. Two of the databases (Northwind and pubs) are sample user databases and can be used as examples, or you can safely delete them (but they don't take up a lot of hard disk space). The other four special system databases (master, model, msdb, and tempdb) are used by the system and should not be removed. To view the databases that are on your SQL Server, in Enterprise Manager expand the group your server is located in, then expand the server, and last expand the Databases folder. Remember, if you have the "Show system databases and system objects" checkbox unchecked in the SQL Server's registration properties, you will be unable to see the system databases in Enterprise Manager.



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master Database -- Contains information about the server overall and all databases created. The information in this database includes: file allocations, disk space usage, system-wide settings, user accounts, and the existence of other databases and other SQL Servers.

model Database -- This database provides a template for all newly created databases. If you ever need to add a table or stored procedures to all the new databases you create, simply modify the model database.

msdb Database -- Used by the SQL Server Agent service.

tempdb Database -- Is a workspace used for holding temporary information.


Books Online

The last topic I want to cover in this article is the SQL Server Books Online (sometimes called BOL) resource. Books Online, located on the start menu under "Programs" > "Microsoft SQL Server", are an invaluable resource. If you ever have a question the first place I would go are the Books Online -- they provide information on just about every topic dealing with SQL Server. One thing you may notice is that the Books Online are also used as the online "help" inside Enterprise Manager.




That finishes it up for this week's (fairly simple) article. Next week we will take a look at database files and we will also create our first database. As always, if you have any technical questions please post them on the SQL message board.Please send any non-technical questions, comments, and feedback to my email. I hope you are finding this series to be a useful one, and I'm looking forward to your feedback.

Mike
maubert@databasejournal.com
www.2000trainers.com


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