Inside Microsoft SQL Server 2008: T-SQL Querying
Table of Contents
Chapter 02: Set Theory and Predicate Logic
Chapter 03: Relational Model
Chapter 04: Query Tuning
Chapter 05: Complexity and Algorithms
Chapter 06: Subqueries, Table Expressions and Ranking Functions
Chapter 07: Joins and Set Operations
Chapter 08: Aggregating and Pivoting Data
Chapter 09: TOP and APPLY
Chapter 10: Data Modification
Chapter 11: Querying Partitioned Tables
Chapter 12: Graphs, Trees, Hierarchies and Recursive Queries
Appendix A: Logic Puzzles
Those who read the SQL Server 2005 edition of the books will find plenty of new materials covering new subjects, new features, and enhancements in SQL Server 2008, plus revisions and new insights about the existing subjects.
These books focus on practical common problems, discussing several approaches to tackle each. You will be introduced to many polished techniques that will enhance your toolbox and coding vocabulary, allowing you to provide efficient solutions in a natural manner.
These books unveil the power of set-based querying and explain why it’s usually superior to procedural programming with cursors and the like. At the same time, they teach you how to identify the few scenarios where cursor-based solutions are superior to set-based ones.
This book—T-SQL Querying—focuses on set-based querying and query tuning, and I recommend that you read it first. The second book—T-SQL Programming—focuses on procedural programming and assumes that you read the first book or have sufficient querying background.
T-SQL Querying starts with five chapters that lay the foundation of logical and physical query processing required to gain the most from the rest of the chapters in both books.
The first chapter covers logical query processing. It describes in detail the logical phases involved in processing queries, the unique aspects of SQL querying, and the special mind-set you need to adopt to program in a relational, set-oriented environment.
The second chapter covers set theory and predicate logic—the strong mathematical foundations upon which the relational model is built. Understanding these foundations will give you better insights into the model and the language. This chapter was written by Steve Kass, who was also the main technical editor of these books. Steve has a unique combination of strengths in mathematics, computer science, SQL, and English that make him the ideal author for this subject.
The third chapter covers the relational model. Understanding the relational model is essential for good database design and helps in writing good code. The chapter defines relations and tuples and operators of relational algebra. Then it shows the relational model from a different perspective called relational calculus. This is more of a business-oriented perspective, as the logical model is described in terms of predicates and propositions. Data integrity is crucial for transactional systems; therefore, the chapter spends time discussing all kinds of constraints. Finally, the chapter introduces normalization—the formal process of improving database design. This chapter was written by Dejan Sarka. Dejan is one of the people with the deepest understanding of the relational model that I know.
The fourth chapter covers query tuning. It introduces a query tuning methodology we developed in our company (SolidQ) and have been applying in production systems. The chapter also covers working with indexes and analyzing execution plans. This chapter provides the important background knowledge required for the rest of the chapters in both books, which as a practice discuss working with indexes and analyzing execution plans. These are important aspects of querying and query tuning.
The fifth chapter covers complexity and algorithms and was also written by Steve Kass. This chapter particularly focuses on some of the algorithms used often by the SQL Server engine. It gives attention to considering worst-case behavior as well as average case complexity. By understanding the complexity of algorithms used by the engine, you can anticipate, for example, how the performance of certain queries will degrade when more data is added to the tables involved. Gaining a better understanding of how the engine processes your queries equips you with better tools to tune them.
The chapters that follow delve into advanced querying and query tuning, addressing both logical and physical aspects of your code. These chapters cover the following subjects: subqueries, table expressions, and ranking functions; joins and set operations; aggregating and pivoting data; TOP and APPLY; data modification; querying partitioned tables; and graphs, trees, hierarchies, and recursive queries.
The chapter covering querying partitioned tables was written by Lubor Kollar. Lubor led the development of partitioned tables and indexes when first introduced in the product, and many of the features that we have today are thanks to his efforts. These days Lubor works with customers who have, among other things, large implementations of partitioned tables and indexes as part of his role in the SQL Server Customer Advisory Team (SQL CAT).
Appendix A covers logic puzzles. Here you have a chance to practice logical puzzles to improve your logic skills. SQL querying essentially deals with logic. I find it important to practice pure logic to improve your query problem-solving capabilities. I also find these puzzles fun and challenging, and you can practice them with the entire family. These puzzles are a compilation of the logic puzzles that I covered in my T-SQL column in SQL Server Magazine. I’d like to thank SQL Server Magazine for allowing me to share these puzzles with the book’s readers.
The second book—T-SQL Programming—focuses on programmatic T-SQL constructs and expands its coverage to treatment of XML and XQuery and the CLR integration. The book’s chapters cover the following subjects: views; user-defi ned functions; stored procedures; triggers; transactions and concurrency; exception handling; temporary tables and table variables; cursors; dynamic SQL; working with date and time; CLR user-defined types; temporal support in the relational model; XML and XQuery (including coverage of open schema); spatial data; tracking access and changes to data (extended events, auditing, change tracking, and change data capture); and Service Broker.
The chapters covering CLR user-defined types, temporal support in the relational model, and XML and XQuery were written by Dejan Sarka. As I mentioned, Dejan is extremely knowledgeable in the relational model and has very interesting insights into the model itself and the way the constructs that he covers in his chapters fit in the model when used sensibly.
The chapter about spatial data was written by Ed Katibah and Isaac Kunen. Ed and Isaac are with the SQL Server development team and led the efforts to implement spatial data support in SQL Server 2008. It is a great privilege to have this chapter written by the designers of the feature. Spatial data support is new to SQL Server 2008 and brings new data types, methods, and indices. This chapter is not intended as an exhaustive treatise on spatial data or as an encyclopedia of every spatial method that SQL Server now supports. Instead, this chapter will introduce core spatial concepts and provide the reader with key programming constructs necessary to successfully navigate this new feature to SQL Server.
The chapter about tracking access and changes to data was written by Greg Low. Greg is a SQL Server MVP and the managing director of SolidQ Australia. Greg has many years of experience working with SQL Server—teaching, speaking, and writing about it—and is highly regarded in the SQL Server community. The technologies that are the focus of this chapter track access and changes to data and are new in SQL Server 2008. At first glance, these technologies can appear to be either overlapping or contradictory, and the best-use cases for each might be far from obvious. This chapter explores each technology, discusses the capabilities and limitations of each, and explains how each is intended to be used.
The last chapter, which covers Service Broker (SSB), was written by Roger Wolter. Roger is the program manager with the SQL Server development team and led the initial efforts to introduce SSB in SQL Server. Again, there’s nothing like having the designer of a component explain it in his own words. The “sleeper” feature of SQL Server 2005 is now in production in a wide variety of applications. This chapter covers the architecture of SSB and how to use SSB to build a variety of reliable asynchronous database applications. The SQL 2008 edition adds coverage of the new features added to SSB for the SQL Server 2008 release and includes lessons learned and best practices from SSB applications deployed since the SQL Server 2005 release. The major new features are Queue Priorities, External Activation, and a new SSB troubleshooting application that incorporates lessons the SSB team learned from customers who have already deployed applications.
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