Database Design and Relational Theory: Normal Forms and All That Jazz

© C. J. Date 2019

C. J. DateDatabase Design and Relational Theoryhttps://doi.org/10.1007/978-1-4842-5540-7_20

Primary Keys Are Nice but Not Essential

C. J. Date¹ 

(1)

Healdsburg, California, USA

 

Life is rather like a tin of sardines—we’re all of us looking for the key.

—Alan Bennett:Beyond the Fringe (1960)

Recall this text from Chapter 1:

• I said it’s usual to choose a primary key. Indeed it is usual—but it’s not 100% necessary. If there’s just one candidate key, then there’s no choice and no problem; but if there are two or more, then having to choose one and make it primary smacks a little bit of arbitrariness, at least to me. (Certainly there are situations where there don’t seem to be any really good reasons for making such a choice. There might ...