SQL and Relational Theory: How to Write Accurate SQL Code Code

石头

作者：C Date
出版日期：February 5, 2009
出版社：O'Reilly
页数：426
ISBN：ISBN-10: 0596523068 ISBN-13: 978-0596523060
文件格式：CHM


Product Description
Understanding SQL’s underlying theory is the best way to guarantee thatyour SQL code is correct and your database schema is robust andmaintainable. On the other hand, if you’re not well versed in thetheory, you can fall into several traps. In SQL and Relational Theory,author C.J. Date demonstrates how you can apply relational theorydirectly to your use of SQL. With numerous examples and clearexplanations of the reasoning behind them, you’ll learn how to dealwith common SQL dilemmas, such as:

• Should database access granted be through views instead of base tables?
• Nulls in your database are causing you to get wrong answers. Why? What can you do about it?
• Could you write an SQL query to find employees who have never been in the same department for more than six months at a time?
• SQL supports “quantified comparisons,” but they’re better avoided. Why? How do you avoid them?
• Constraints are crucially important, but most SQL products don’tsupport them properly. What can you do to resolve this situation?

Database theory and practice have evolved since Edgar Coddoriginally defined the relational model back in 1969. Independent ofany SQL products, SQL and Relational Theory draws on decadesof research to present the most up-to-date treatment of the materialavailable anywhere. Anyone with a modest to advanced background in SQLwill benefit from the many insights in this book.
About the Author
C.J. Date has a stature that is unique within the database industry.C.J. is a prolific writer, and is well-known for his best-sellingtextbook: An Introduction to Database Systems (Addison Wesley). C.J. isan exceptionally clear-thinking writer who can lay out principles andtheory in a way easily understood by his audience.

Jamesliu2009