Codd’s 12 Rules (for a relational database product) are (still) frequently informally cited, but their original text turns out to be annoyingly difficult to find. They are reprinted here under the principles of fair use and/or fair dealing and have been extracted, verbatim, from ‘Is your DBMS really relational?’, Computerworld. Oct 14, 1985, Vol. 19, Read more about Codd’s Twelve Rules[…]