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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Large databases
> BIRTH_DATE DATE,
> AGE NUMBER(3),
Derived information - eliminate
Age is not necessarily a derived value. In the some businesses (ie POLICE)
you may only have an age without a DOB.
>From age you can derive a YOB (year of birth) but that cannot be stored
properly in a date field so you need a field other than DOB.
Debbie
-----Original Message-----
Sent: Wednesday, April 16, 2003 3:19 PM
To: Multiple recipients of list ORACLE-L
Note inline
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk
The educated person is not the person who can answer the questions, but the person who can question the answers -- T. Schick Jr
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> CREATE TABLE PERSON (
> PERSON_ID NUMBER,
> FNAME VARCHAR2(20),
> MNAME VARCHAR2(20),
> LNAME VARCHAR2(30),
Denormalize names - First/Middle/Last is not the only option:
(person_id, name_position, name)
> RACE_ID NUMBER(25), /*allows for proliferation
> of pc categories */
Denomralize:
(person_id, race_id, percentage)
> BIRTH_DATE DATE,
> AGE NUMBER(3),
Derived information - eliminate
> HANDEDNESS CHAR(1),
> SEX CHAR(1),
Denormalize:
(person_id, date_form, sex)
> HEIGHT NUMBER(3),
Denomralize
(person_id, date_measured, height)
> WEIGHT NUMBER(3),
as above
> WAIST NUMBER(2),
as above
> INSEAM NUMBER(2),
(person_id, left_right, date_measured, length)
> COLLAR NUMBER(2),
as waist
> ARM_LEN VARCHAR2(5),
as inseam
> HAT_SIZE VARCHAR2(4),
as waist
> SHOE_SIZE VARCHAR2(5),
as inseam
> EYE_COLOR_CD VARCHAR2(3),
(person_id, left_right, colour_code)
> HAIR_COLOR_CD VARCHAR2(3),
(person_id, date_measured, colour_code)
> MARRIED CHAR(1),
(person_id, date_from, status)
> EDUCATION_CD NUMBER(1),
(person_id, date_achieved, code)
which brings us down to:
person_id
birth_date
handedness -- (but what if you lost your arm, and learned ?!)
Um !
> Now, that's over 20 and afaik normalized, no repeating groups, no
> dependency on non key atttibutes, just to point out that aribitrary
> numerical limits don't mean much if no business requirements are in
> view.
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Jonathan Lewis INET: jonathan_at_jlcomp.demon.co.uk Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: IT - Database (Do Not Use) INET: dbamail_at_police.edmonton.ab.ca Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Thu Apr 17 2003 - 09:42:09 CDT
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