Database design question

#31

On 2008-11-01, Charles Calvert <cbciv (AT) yahoo (DOT) com> wrote:

Quote:

CREATE TABLE phones (
phone_id INT PRIMARY KEY,
sim_id INT NULL,
CONSTRAINT FK_phones_sims FOREIGN KEY
(sim_id) REFERENCES sims (sim_id)
);

would not violate the 3NF.

allowing nulls violates 3NF

Bye.
Jasen

#32

Jasen Betts <jasen (AT) xnet (DOT) co.nz> wrote:

Quote:

On 2008-11-01, Charles Calvert <cbciv (AT) yahoo (DOT) com> wrote:
CREATE TABLE phones (
phone_id INT PRIMARY KEY,
sim_id INT NULL,
CONSTRAINT FK_phones_sims FOREIGN KEY
(sim_id) REFERENCES sims (sim_id)
);

would not violate the 3NF.

allowing nulls violates 3NF
^^^

ITYM "1NF".

Sincerely,

Gene Wirchenko

Computerese Irregular Verb Conjugation:
I have preferences.
You have biases.
He/She has prejudices.

#33

Jasen Betts <jasen (AT) xnet (DOT) co.nz> wrote:

Quote:

On 2008-11-01, Charles Calvert <cbciv (AT) yahoo (DOT) com> wrote:
CREATE TABLE phones (
phone_id INT PRIMARY KEY,
sim_id INT NULL,
CONSTRAINT FK_phones_sims FOREIGN KEY
(sim_id) REFERENCES sims (sim_id)
);

would not violate the 3NF.

allowing nulls violates 3NF
^^^

ITYM "1NF".

Sincerely,

Gene Wirchenko

Computerese Irregular Verb Conjugation:
I have preferences.
You have biases.
He/She has prejudices.

#34

Jasen Betts <jasen (AT) xnet (DOT) co.nz> wrote:

Quote:

On 2008-11-01, Charles Calvert <cbciv (AT) yahoo (DOT) com> wrote:
CREATE TABLE phones (
phone_id INT PRIMARY KEY,
sim_id INT NULL,
CONSTRAINT FK_phones_sims FOREIGN KEY
(sim_id) REFERENCES sims (sim_id)
);

would not violate the 3NF.

allowing nulls violates 3NF
^^^

ITYM "1NF".

Sincerely,

Gene Wirchenko

Computerese Irregular Verb Conjugation:
I have preferences.
You have biases.
He/She has prejudices.

#35

On 2 Nov 2008 02:00:10 GMT, Jasen Betts <jasen (AT) xnet (DOT) co.nz> wrote in
<gej1ja$1a1$1 (AT) reversiblemaps (DOT) ath.cx>:

Quote:

On 2008-11-01, Charles Calvert <cbciv (AT) yahoo (DOT) com> wrote:
CREATE TABLE phones (
phone_id INT PRIMARY KEY,
sim_id INT NULL,
CONSTRAINT FK_phones_sims FOREIGN KEY
(sim_id) REFERENCES sims (sim_id)
);

would not violate the 3NF.

allowing nulls violates 3NF

How so?
--
Charles Calvert | Web-site Design/Development
Celtic Wolf, Inc. | Software Design/Development
http://www.celticwolf.com/ | Data Conversion
(703) 580-0210 | Project Management

#36

On Mon, 03 Nov 2008 20:38:50 -0800, Gene Wirchenko <genew (AT) ocis (DOT) net>
wrote in <6ekvg419bm11psovs2lhvm1ibdckh0pn0s (AT) 4ax (DOT) com>:

Quote:

Jasen Betts <jasen (AT) xnet (DOT) co.nz> wrote:

On 2008-11-01, Charles Calvert <cbciv (AT) yahoo (DOT) com> wrote:
CREATE TABLE phones (
phone_id INT PRIMARY KEY,
sim_id INT NULL,
CONSTRAINT FK_phones_sims FOREIGN KEY
(sim_id) REFERENCES sims (sim_id)
);

would not violate the 3NF.

allowing nulls violates 3NF
^^^
ITYM "1NF".

I find this even less likely than the assertion that they violate the
3NF. Why do you believe it to be so?
--
Charles Calvert | Web-site Design/Development
Celtic Wolf, Inc. | Software Design/Development
http://www.celticwolf.com/ | Data Conversion
(703) 580-0210 | Project Management

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Database design question

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