From oracle-l-bounce@freelists.org Mon Aug 8 08:59:15 2005 Return-Path: Received: from air891.startdedicated.com (root@localhost) by orafaq.com (8.12.10/8.12.10) with ESMTP id j78DxEao001077 for ; Mon, 8 Aug 2005 08:59:14 -0500 X-ClientAddr: 206.53.239.180 Received: from turing.freelists.org (freelists-180.iquest.net [206.53.239.180]) by air891.startdedicated.com (8.12.10/8.12.10) with ESMTP id j78Dx8IP001053 for ; Mon, 8 Aug 2005 08:59:08 -0500 Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 6F4041DD4EA; Mon, 8 Aug 2005 08:59:06 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 14029-08; Mon, 8 Aug 2005 08:59:06 -0500 (EST) Received: from turing (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id CB1811DCA69; Mon, 8 Aug 2005 08:59:05 -0500 (EST) X-MimeOLE: Produced By Microsoft Exchange V6.5.7226.0 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C59C21.139DA316" Subject: RE: Counterquestion - is Oracle a He or a She - or an It or a hermaphrodite Date: Mon, 8 Aug 2005 06:53:09 -0700 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Counterquestion - is Oracle a He or a She - or an It or a hermaphrodite Thread-Index: AcWcFIxvBkVTcfk0SwC63yRampTulQAC/ZrH From: "Kennedy, Jim" To: "Niall Litchfield" Cc: , X-OriginalArrivalTime: 08 Aug 2005 13:57:13.0230 (UTC) FILETIME=[13F05AE0:01C59C21] X-archive-position: 23543 X-ecartis-version: Ecartis v1.0.0 Sender: oracle-l-bounce@freelists.org Errors-To: oracle-l-bounce@freelists.org X-original-sender: jim_kennedy@mentor.com Precedence: normal Reply-To: jim_kennedy@mentor.com X-list: oracle-l X-Virus-Scanned: by amavisd-new-20030616-p9 (Debian) at avenirtech.net X-mailscan-MailScanner-Information: Please contact the ISP for more information X-mailscan-MailScanner: Found to be clean X-MailScanner-From: oracle-l-bounce@freelists.org X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on air891.startdedicated.com X-Spam-Status: No, hits=-4.8 required=5.0 tests=AWL,BAYES_00,HTML_MESSAGE autolearn=ham version=2.63 ------_=_NextPart_001_01C59C21.139DA316 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable -----Original Message----- From: Niall Litchfield [mailto:niall.litchfield@gmail.com] Sent: Mon 8/8/2005 5:27 AM To: Kennedy, Jim Cc: psinger1@chartermi.net; oracle-l@freelists.org Subject: Re: Counterquestion - is Oracle a He or a She - or an It or a = hermaphrodite =20 Comments below On 8/6/05, Kennedy, Jim wrote:=20 >=20 >=20 >=20 > I explain NULLS in the following manner. >=20 > Imagine a medical application where your medical data is stored in a > database. Imagine that your Dr. has never asked you if you have > allergies or not. Further imagine that you become unconcouse and go to > the emergency room. The Dr. in the emergency room looks at your > electronic medical data. Given the information in your electronic = chart > what should the Dr. assume about your allergic reactions?: > A. You are Alergic to something. > B. You are not allergic to anything. > C. It is unknown if you are or are not allergic to anything. >=20 > The Dr. should assume C. You have not been asked the question so the > data in that column is NULL and the Dr. should make NO assumptions = about > your medical condition visa vis allergys. In medicine even if they > asked you the question "Are you allergic to anything?" and you = answered > "No" the correct value to store is NKA - No Known Allergies. After > this explanation most people understand what a NULL is. > Jim Isn't this a great example of how a better design is a better solution? = Wouldn't=20 PATIENT =3D=3D=3D=3D=3D=3D=3D PATIENT_PK .................... ALLERGEN =3D=3D=3D=3D=3D=3D=3D=3D=3D ALLERGEN_PK ........................ KNOWN_ALLERGIES =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D PATIENT_PK -- foreign key ALLERGEN_PK -- foreign key IDENTIFIED_DATE ..... Be a better design? Then the doctor would just pull up a list of known=20 allergies (which might of course be empty). This is a lot different, and = I'd=20 argue better, than pulling up a NKA or NULL value.=20 --=20 Niall Litchfield Oracle DBA http://www.niall.litchfield.dial.pipex.com Sorry if I wasn't clear enough. NULL!=3DNKA. They are very different. = NKA means the Dr. asked the question and the patient said I don't have = any allergies. (So they don't have any known allergies. They still = might be allergic to something, but there aren't any known allergies.) So yes, if the person has one or more allergies there was an allergy = table. If they didn't have any known allergies NKA was one of the = entries on the allergy table. But if they hadn't been asked then the = key was NULL.(we don't know if they are or are not allergic to anything = and we have not asked them the question.) Jim ------_=_NextPart_001_01C59C21.139DA316 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable RE: Counterquestion - is Oracle a He or a She - or an It or a = hermaphrodite


-----Original Message-----
From: Niall Litchfield [mailto:niall.litchfield@gmail.= com]
Sent: Mon 8/8/2005 5:27 AM
To: Kennedy, Jim
Cc: psinger1@chartermi.net; oracle-l@freelists.org
Subject: Re: Counterquestion - is Oracle a He or a She - or an It or a = hermaphrodite

Comments below
On 8/6/05, Kennedy, Jim <jim_kennedy@mentor.com> wrote:
>
>
>
> I explain NULLS in the following manner.
>
> Imagine a medical application where your medical data is stored in = a
> database. Imagine that your Dr. has never asked you if you have
> allergies or not. Further imagine that you become unconcouse and go = to
> the emergency room. The Dr. in the emergency room looks at your
> electronic medical data. Given the information in your electronic = chart
> what should the Dr. assume about your allergic reactions?:
> A. You are Alergic to something.
> B. You are not allergic to anything.
> C. It is unknown if you are or are not allergic to anything.
>
> The Dr. should assume C. You have not been asked the question so = the
> data in that column is NULL and the Dr. should make NO assumptions = about
> your medical condition visa vis allergys. In medicine even if = they
> asked you the question "Are you allergic to anything?" = and you answered
> "No" the correct value to store is NKA - No Known = Allergies. After
> this explanation most people understand what a NULL is.
> Jim

 Isn't this a great example of how a better design is a better = solution?
Wouldn't
 PATIENT
=3D=3D=3D=3D=3D=3D=3D
PATIENT_PK
....................
 ALLERGEN
=3D=3D=3D=3D=3D=3D=3D=3D=3D
ALLERGEN_PK
........................
 KNOWN_ALLERGIES
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
PATIENT_PK -- foreign key
ALLERGEN_PK -- foreign key
IDENTIFIED_DATE
.....

Be a better design? Then the doctor would just pull up a list of = known
allergies (which might of course be empty). This is a lot different, and = I'd
argue better, than pulling up a NKA or NULL value.

--
Niall Litchfield
Oracle DBA
http://www.niall.litc= hfield.dial.pipex.com


Sorry if I wasn't clear enough.  NULL!=3DNKA.  They are very = different.  NKA means the Dr. asked the question and the patient = said I don't have any allergies. (So they don't have any known = allergies.  They still might be allergic to something, but there = aren't any known allergies.)

So yes, if the person has one or more allergies there was an allergy = table.  If they didn't have any known allergies NKA was one of the = entries on the allergy table.  But if they hadn't been asked then = the key was NULL.(we don't know if they are or are not allergic to = anything and we have not asked them the question.)


Jim

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