David Cressey wrote:
...
> SQL oriented people (I might include myself) will advocate declaring a
> primary key whenever a table is created, and making all FK references to
> the table via its primary key. That turns out to be of value even if the
> primary key concept is outside of the relational model of data.
Maybe pre-dated but surely not outside? Codd said something like
"because it's there" not long after John Lennon said "you know my name,
look up my number". From the perspective of a single relation, it does
seem to stand for the "primary candidate inference"! At least "primary
key" is better than "primary unique key"! I wish Codd had just called
it the declared inference but I suppose that may have scared off his
often crude audience.
Received on Thu Jul 12 2007 - 14:33:50 CDT
