Interesting article. Most of things are well known, but here they are summarized and there are also some interesting ideas.
The most curious for me was this one:
I can not imagine any practical use of below code, but theoretically it is possible.
CREATE TABLE master( pkey int PRIMARY KEY FOREIGN KEY (pkey) REFERENCES master(pkey))
It really does nothing. I hoped it will prevent update of PK and deleting a record,
so I tried it, but unfortunately it doesn't prevent either PK update nor record deleting.