Domains and Types in Relational Theory and SQL: Shedding Some Light on a Widely Misunderstood Concept

Date, Chris

ISBN 10: 1634625447 / ISBN 13: 9781634625449

Published by Technics Publications, 2024

About this Item

Seller Inventory # I-9781634625449

Bibliographic Details

• Title: Domains and Types in Relational Theory and SQL: Shedding Some Light on a Widely Misunderstood Concept
• Publisher: Technics Publications
• Publication Date: 2024
• Language: English
• ISBN 10: 1634625447
• ISBN 13: 9781634625449
• Binding: Soft cover
• Condition: New

About this title

Synopsis

What’s a domain? What’s a type? The original version of the relational model (defined by Codd in 1969) had domains and not types. The original version of the SQL standard (defined by committee in 1986, but based on work done by Boyce and Chamberlin et al. in the 1970s) had types and not domains. Later, Codd added types and SQL added domains. But no two of these constructs—domains per Codd, types per Codd, domains per SQL, types per SQL—are the same thing! Other researchers, designers, and implementers then got into the act with further definitions of their own, and the picture became, and remains, more confused than ever. This book is an attempt to clear the air. To be specific, it argues that:

• Domains per Codd aren’t really domains in the mathematical sense but are much closer to types in the computing sense, and types per Codd don’t belong in the model at all.
• Types per SQL are really several different concepts all mixed together in confusing ways, and domains per SQL are just a red herring.
• Properly understood, domains and types are the same thing after all.

The book justifies these claims by describing and analyzing the pertinent aspects of both SQL and the relational model in detail.

About the Author

Chris Date has a stature that is unique in the database industry. He is best known for his textbook An Introduction to Database Systems (Addison-Wesley), which has sold close to a million copies at the time of writing. He enjoys a reputation that is second to none for his ability to explain complex technical issues in a clear and understandable fashion. He was inducted into the Computing Industry Hall of Fame in 2004.