Confessions of an IT Manager_Phil Factor

282 The Ballad of the Tuple Relation
You might be thinking 'Phew, hot stuff', but I couldn't make much sense of
it. In fact, were I ever to be abducted by extraterrestrial aliens, I will expect
them to address me in similar unfathomable clicks and whirrs before
conducting their foul experiments upon my person.
It was whilst I was fruitlessly re-reading the definition for the fifth time,
trying to decipher some meaning from it, I began to wonder whether, in fact, it
was a poem. I give the first two resonant stanzas
Let r be a relation and I will tell you why;
let the heading of r be partitioned into subsets {X} and {Y}.
Let the attributes of {Y} be Yl, Y2, ..., Yn; also
let {X} not contain any attribute called YR though.
The heading, now, of s consists of {X} extended by
an attribute YR of type RELATION {Y}.
The body of s is defined as follows: See!
first, let z be the result of r WRAP ({Y} AS YT).
Second, for each distinct X value x in z,
(a) let yr be the relation whose tuples be
all and only those YT values, as anyone expects
from tuples in z in which the X value is x;
... and so on. Quite the sort of output one might expect of a post-modernist
poet.
But then, after having extracted as much amusement out of the paragraphs
as I could, I felt a certain twinge of sadness. Robyn and I are both firmly of the
belief there is nothing in relational database theory or practice that cannot be
explained to an interested child. SQL is merely a formalised dialect of English
that describes action. I firmly believe that a relational database can be made so
simple that any educated person can use it. Codd formalised the theory for the
automation of existing processes that existed long before the first computers. It
is the language of information retrieval.