Microsoft® SQL Server™ 2000 Unleashed, Second Edition

Chapter 14. Implementing Data Integrity

by Paul Jensen

IN THIS CHAPTER

• Types of Data Integrity

• Enforcing Data Integrity

• Constraints

• Rules

• Defaults

Ensuring the integrity of data is one of the most important tasks of an administrator. Key business decisions are often made based on information in the database; if the data is misrepresented, incorrect conclusions might be drawn. Consider a car manufacturer who uses a product code R01 (R zero one) to represent every red car sold. To predict next year's sales of red cars, they run a query on the database to count the instances of R01. They determine that they sold far fewer red cars than expected, and reduce production. Halfway through the year, they run out of red cars. On closer inspection of the data, ...