Apress - Pro SQL Server 2008 Relational Database Design and Implementation (2008)02

Apress - Pro SQL Server 2008 Relational Database Design and Implementation (2008)02
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Apress - Pro SQL Server 2008 Relational Database Design and Implementation (2008)02xiv sCONTENTS Character Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 619 char[(length)] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 619 varchar[(length)]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 620 varchar(max) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 621 text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 622 Unicode Character Strings: nchar, nvarchar, nvarchar(max), ntext . . . . . 622 Binary Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623 binary[(length)] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623 varbinary[(length)] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 624 varbinary(max) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 624 image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625 Other Datatypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625 rowversion (a.k.a. timestamp) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625 uniqueidentifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 626 cursor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 629 table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 629 sql_variant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632 Not Simply Scalar Datatypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 633 sINDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 635ForewordD atabase design is a passion that Louis and I share. This fall, I will be fortunate to share a stage withmy friend, Louis Davidson. We’re copresenting at DevLink in Louis’s hometown of Nashville and thenagain at PASS in Seattle. Both times, we’ll discuss, debate, and celebrate the topic of database designand how critical it is for any datacentric application. Database design is part science and part art. There’s a science to normalization, but determiningthe scope of the entity is an art form best learned from working with a broad repertoire of databases.There’s a simple beauty to an elegant solution. Louis is more than an author or database designer;Louis is a master artisan, and in this book, you’ll discover hidden within the words a call to improveyour craft, to sculpt databases that stand the test of time, and to create virtual worlds of data thatenable developers to play their best game. Database design is the foundation of every datacentric application. An elegant database designmakes the data obvious and easy to query and sets up the developer for success with efficient set-based queries. But, no amount of code can compensate for a poor database design or add featuresmissing from the database. No role is more critical to any datacentric application than the role ofthe data modeler. User interfaces come and go, but data lasts for generations of application lan-guages, and today’s database schema errors will be cursed by programmers not yet born usinglanguages and tools not yet invented. It’s worth spending a little extra time to polish your databasedesign under the tutelage of my good friend, Louis. So it’s with great pleasure that I welcome you to this third edition of Louis’s field guide to thegreatest job in the world of software. Paul Nielsen SQL Server MVP xvAbout the AuthorsLOUIS DAVIDSON has over 15 years of experience as a corporate databasedeveloper and architect. Currently, he is the data architect for the Christ-ian Broadcasting Network and NorthStar Studios in Nashville, Tennessee.Nearly all of Louis’s professional experience has been with Microsoft SQLServer, from the early days to the latest version currently in beta. Louis hasbeen the principal author on four editions of a book on database design.Louis’s primary areas of interest are database architecture and coding inT-SQL, and he has experience designing many databases and writingthousands of stored procedures and triggers through the years. ...