Keys, Locators, and Generated Values
Abstract
Tables used logical keys to locate data as opposed to pointers and other physical devices. I discuss my classification system for keys.
Keywords
Keys
Locators
Generated values
Compound key
IDENTITY
Natural key
Artificial key
Exposed physical locator
Surrogate key
GUID
Denormalization
Donald Knuth
Key is an unfortunate term in IT. We have encryption keys, sort keys, access keys, and probably a dozen other uses for the term I cannot think of right now. Unless I explicitly say otherwise, I will mean a relational key in this book. A (relational) key is a subset of one or more columns in a table which are guaranteed unique for all possible rows. If there is more than one column in the subset, this is a compound ...
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