SQL is full of difficulties and traps for the
unwary. You can avoid them if you understand relational
theory, but only if you know how to put the theory into
practice. In this insightful book, author C.J. Date
explains relational theory in depth, and demonstrates
through numerous examples and exercises how you can
apply it directly to your use of SQL.
This second
edition includes new material on recursive queries,
“missing information” without nulls, new update
operators, and topics such as aggregate operators,
grouping and ungrouping, and view updating. If you have
a modest-to-advanced background in SQL, you’ll learn how
to deal with a host of common SQL dilemmas.
- Why is proper column naming so important?
- Nulls in your database are causing you to get
wrong answers. Why? What can you do about it?
- Is it possible to 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’t support them properly. What can you do
to resolve this situation?
Database theory
and practice have evolved since the relational model was
developed more than 40 years ago. SQL and Relational
Theory draws on decades of research to present the most
up-to-date treatment of SQL available.
C.J.
Date has a stature that is unique within the
database industry. A prolific writer well known for the
bestselling textbook
An Introduction to Database
Systems (Addison-Wesley), he has an exceptionally
clear style when writing about complex principles and
theory.
