Re: does a table always need a PK?

Hi!

I would like to bring up to the discussion what I remarked in the other discussion thread on MySQL RDBMSness.

If we have a quantum mechanical system where electrons are indistinguishable, would it not be natural to create a table of electrons without a primary key?

Best regards,

Heikki Tuuri
Innobase Oy

"--CELKO--" <joe.celko_at_northface.edu> kirjoitti viestissä news:a264e7ea.0308231444.3179b3a3_at_posting.google.com...
> >> do I need to have a primary key in the BOOK table? <<
>
> Yes, otherwise it is not a table by definition. Assuming that you
> have more than one book, use the ISBN as the industry standard
> identifier and use this table:
>
> CREATE TABLE Books
> (isbn CHAR(10) NOT NULL,
> page_nbr INTEGER NOT NULL,
> content TEXT NOT NULL,
> PRIMARY KEY (isbn, page_nbr));
>
> if you had only one book, use its title for the table name:
>
> CREATE TABLE "Moby Dick"
> (page_nbr INTEGER NOT NULL PRIMARY KEY,
> content TEXT NOT NULL);
>
> You are splitting attributes in the original schema. That is, you put
> the attributes of a book in (n > 1) table, so the data model was not
> complete.
Received on Sun Aug 24 2003 - 20:07:17 CEST