SQL and Relational Theory

Kurzbeschreibung:

SQL is full of difficulties and traps for the unwary. Understanding relational theory is essential for avoiding those traps, but you need to know how to map the ideas of that theory into SQL code. In SQL and Relational Theory, author C.J. Date demonstrates how you can apply relational theory directly to your use of SQL.
The second edition includes updated material such as recursive queries, new operators, and extended discussion of topics including aggregate operators, grouping and ungrouping, and view updating. With numerous examples, exercises, and clear explanations, you ll learn how to deal with common SQL dilemmas, such as:
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?
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 t support them properly. What can you do to resolve this situation?
SQL and Relational Theory draws on decades of research to present the most up-to-date treatment of the material available anywhere. Anyone with a modest to advanced background in SQL will benefit from the many insights in this book.

Klappentext:

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.

Themen:

• Relationale Datenbank
• SQL (Structured Query Language)

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