Database Normalization Raymond Mark/Learn iT! Incorporated.

Database NormalizationDatabase NormalizationRaymond Mark/Learn iT! IncorporatedRaymond Mark/Learn iT! Incorporated

What Is Normalization?What Is Normalization?

Process of modifying a database into Process of modifying a database into different normal forms (stages of different normal forms (stages of normalization)normalization)

Process of organizing data to eliminate Process of organizing data to eliminate repetitionrepetition

Process of organizing data to make a Process of organizing data to make a database more efficientdatabase more efficient

Normal FormsNormal Forms

First Normal FormFirst Normal Form Flat file tablesFlat file tables No field repetitionNo field repetition

Second Normal FormSecond Normal Form Meets all First Normal Form requirementsMeets all First Normal Form requirements Non-key attributes are functionally dependent Non-key attributes are functionally dependent

on primary keyon primary key


Third Normal FormThird Normal Form(Boyce-Codd Normal Form, BCNF)(Boyce-Codd Normal Form, BCNF) Meets all Second Normal Form requirementsMeets all Second Normal Form requirements Eliminates all fields not fully dependent on the Eliminates all fields not fully dependent on the

primary key fieldprimary key field


Fourth Normal FormFourth Normal Form Meets all Third Normal Form requirementsMeets all Third Normal Form requirements Given relation may not contain more than one Given relation may not contain more than one

multivalued attributemultivalued attribute

Fifth Normal FormFifth Normal Form Meets all Third Normal Form requirementsMeets all Third Normal Form requirements Contains data that enables reconstruction of Contains data that enables reconstruction of

original data sourceoriginal data source

Database Design GuidelinesDatabase Design Guidelines

Spend the bulk of your effort on table and Spend the bulk of your effort on table and relational designrelational designConsider the tradeoff between Consider the tradeoff between normalization rules and actual data usagenormalization rules and actual data usageEstablish table objects and relationships Establish table objects and relationships before creating other MS Access objectsbefore creating other MS Access objectsUse consistent naming conventionsUse consistent naming conventionsTest your objects and design before fully Test your objects and design before fully populating tablespopulating tables

Normalizing GuidelinesNormalizing Guidelines

Make Your Data AtomicMake Your Data Atomic

Avoid Field RepetitionAvoid Field Repetition

Avoid Data RepetitionAvoid Data Repetition

Make Primary Keys Short and StableMake Primary Keys Short and Stable

Maintain Table RelevanceMaintain Table Relevance

Maintain Field IndependenceMaintain Field Independence

Rule 1: Make Your Data AtomicRule 1: Make Your Data Atomic

Break the data into fields that are as small Break the data into fields that are as small as usably possibleas usably possible

It’s easier to search for information when It’s easier to search for information when the data are in their own fieldsthe data are in their own fields

In MS Access, it’s easier to fuse two In MS Access, it’s easier to fuse two pieces of data into one than the other way pieces of data into one than the other way aroundaround

Rule 1: Make Your Data AtomicRule 1: Make Your Data Atomic

strNamestrName strAddressstrAddress

Isabelle RingingIsabelle Ringing 10 Main Street10 Main Street

Boston, MA 02134Boston, MA 02134

Johnny Walker-Johnny Walker-BlackBlack

2588 California Street2588 California Street

San Francisco, CA 94109San Francisco, CA 94109

strFNamestrFName strLNamestrLName strStreetstrStreet strCitystrCity strStatestrState strZIPstrZIP

IsabelleIsabelle RingingRinging 10 Main 10 Main StreetStreet

BostonBoston MAMA 0213402134

JohnnyJohnny Walker-Walker-BlackBlack

2588 2588 California California StreetStreet

San San FranciscoFrancisco

CACA 9410994109

Rule 2: Avoid Field RepetitionRule 2: Avoid Field Repetition

This rule helps to achieveThis rule helps to achieveFirst Normal FormFirst Normal Form

In most cases of field repetition, the In most cases of field repetition, the number of fields that may eventually be number of fields that may eventually be required is usually unknown.required is usually unknown.


Fields that are repeated may make you set Fields that are repeated may make you set aside memory that you never fill with dataaside memory that you never fill with data

Fields that are repeated have to be Fields that are repeated have to be searched on individually, increasing the searched on individually, increasing the demands on a data searchdemands on a data search

Separate repeating fields into their own Separate repeating fields into their own table, unifying the fields in the processtable, unifying the fields in the process


lngInvNolngInvNo dtmDatedtmDate strItem01strItem01 intQnt0intQnt011

strItem02strItem02 intQnt0intQnt022

strItem03strItem03 intQnt03intQnt03

778309778309 05/10/0205/10/02 StaplesStaples(case)(case)

2020 Board FluidBoard Fluid

(6 oz.)(6 oz.)

1515

778310778310 05/10/0205/10/02 PencilsPencils

(dozen)(dozen)

1010 Binder ClipsBinder Clips

(case)(case)

1010 Coffee Coffee MugsMugs

66

778311778311 05/11/0205/11/02 Coffee Coffee MugsMugs

1010


lngInvNolngInvNo dtmDatedtmDate

778309778309 05/10/0205/10/02

778310778310 05/10/0205/10/02

778311778311 05/11/0205/11/02

lngInvNolngInvNo strItemstrItem intQuantityintQuantity

778309778309 Staples (case)Staples (case) 2020

778309778309 Board Fluid (6 oz.)Board Fluid (6 oz.) 1515

778310778310 Pencils (dozen)Pencils (dozen) 1010

778310778310 Binder Clips Binder Clips (case)(case)

1010

778310778310 Coffee MugsCoffee Mugs 66



lngInvNolngInvNoPKPK dtmDatedtmDate

778309778309 05/10/0205/10/02

778310778310 05/10/0205/10/02

778311778311 05/11/0205/11/02

lngInvNolngInvNoFKFK strItemstrItem intQuantityintQuantity

778309778309 Staples (case)Staples (case) 2020

778309778309 Board Fluid (6 oz.)Board Fluid (6 oz.) 1515

778310778310 Pencils (dozen)Pencils (dozen) 1010

778310778310 Binder Clips Binder Clips (case)(case)

1010



Rule 3: Avoid Data RepetitionRule 3: Avoid Data Repetition

This rule helps to achieveThis rule helps to achieveSecond Normal FormSecond Normal Form

When data entry is repeated, it’s an When data entry is repeated, it’s an indication that the information should be indication that the information should be consolidated into a single reference pointconsolidated into a single reference point

The reference point for the consolidated The reference point for the consolidated data is that row’s data is that row’s Primary KeyPrimary Key

Rule 3: Avoid Data RepetitionRule 3: Avoid Data Repetition

strFNamestrFName strLNamestrLName strStreetstrStreet strCitystrCity strStatestrState strZIPstrZIP sngHrssngHrs dtmDatedtmDate

IsabelleIsabelle RingingRinging 10 Main Street10 Main Street BostonBoston MAMA 0213402134 5.55.5 05/01/0205/01/02

AnitaAnita ManhattanManhattan 2588 Pine Street2588 Pine Street OaklandOakland CACA 9410994109 7.07.0 05/04/0205/04/02

HarryHarry ArmpitsArmpits 452 Dove Road452 Dove Road BostonBoston MAMA 0213402134 6.06.0 05/08/0205/08/02

MonaMona LottLott 98 Kelly Place98 Kelly Place ChicagoChicago ILIL 6061460614 6.56.5 05/08/0205/08/02

BenBen DoverDover 55 Willow Avenue55 Willow Avenue ChicagoChicago ILIL 6061460614 7.57.5 05/10/0205/10/02

IsabelleIsabelle RingingRinging 10 Main Street10 Main Street BostonBoston MAMA 0213402134 6.06.0 05/11/0205/11/02

MonaMona LottLott 98 Kelly Place98 Kelly Place ChicagoChicago ILIL 6061460614 5.05.0 05/11/0205/11/02

BenBen DoverDover 55 Willow Avenue55 Willow Avenue ChicagoChicago ILIL 6061460614 7.57.5 05/11/0205/11/02

AnitaAnita ManhattanManhattan 2588 Pine Street2588 Pine Street OaklandOakland CACA 9410994109 6.56.5 05/14/0205/14/02

HarryHarry ArmpitsArmpits 452 Dove Road452 Dove Road BostonBoston MAMA 0213402134 6.56.5 05/15/0205/15/02

Rule 3: Avoid Data RepetitionRule 3: Avoid Data RepetitionstrFNamestrFName strLNamestrLName strStreetstrStreet strCitystrCity strStatestrState strZIPstrZIP

IsabelleIsabelle RingingRinging 10 Main Street10 Main Street BostonBoston MAMA 0213402134

AnitaAnita ManhattanManhattan 2588 Pine Street2588 Pine Street OaklandOakland CACA 9410994109

HarryHarry ArmpitsArmpits 452 Dove Road452 Dove Road BostonBoston MAMA 0213402134

MonaMona LottLott 98 Kelly Place98 Kelly Place ChicagoChicago ILIL 6061460614

BenBen DoverDover 55 Willow Avenue55 Willow Avenue ChicagoChicago ILIL 6061460614

strIDPKstrIDPK

IR255IR255

AM892AM892

HA883HA883

ML556ML556

BD418BD418

strIDFKstrIDFK sngHrssngHrs dtmDatedtmDate

IRIR 5.55.5 05/01/0205/01/02

AMAM 7.07.0 05/04/0205/04/02

HAHA 6.06.0 05/08/0205/08/02

MLML 6.56.5 05/08/0205/08/02

BDBD 7.57.5 05/10/0205/10/02

IRIR 6.06.0 05/11/0205/11/02

MLML 5.05.0 05/11/0205/11/02

BDBD 7.57.5 05/11/0205/11/02

AMAM 6.56.5 05/14/0205/14/02

HAHA 6.56.5 05/15/0205/15/02

Rule 3: Avoid Data RepetitionRule 3: Avoid Data RepetitionstrFNamestrFName strLNamestrLName strStreetstrStreet strZIPstrZIP

IsabelleIsabelle RingingRinging 10 Main Street10 Main Street 0213402134

AnitaAnita ManhattanManhattan 2588 Pine Street2588 Pine Street 9410994109

HarryHarry ArmpitsArmpits 452 Dove Road452 Dove Road 0213402134

MonaMona LottLott 98 Kelly Place98 Kelly Place 6061460614

BenBen DoverDover 55 Willow Avenue55 Willow Avenue 6061460614

strIDPKstrIDPK

IR255IR255

AM892AM892

HA883HA883

ML556ML556

BD418BD418

strIDFKstrIDFK sngHrssngHrs dtmDatedtmDate

IRIR 5.55.5 05/01/0205/01/02

AMAM 7.07.0 05/04/0205/04/02

HAHA 6.06.0 05/08/0205/08/02

MLML 6.56.5 05/08/0205/08/02

BDBD 7.57.5 05/10/0205/10/02

IRIR 6.06.0 05/11/0205/11/02

MLML 5.05.0 05/11/0205/11/02

BDBD 7.57.5 05/11/0205/11/02

AMAM 6.56.5 05/14/0205/14/02

HAHA 6.56.5 05/15/0205/15/02

strZIPstrZIP strCitystrCity strStatestrState

0213402134 BostonBoston MAMA

9410994109 OaklandOakland CACA

6061460614 ChicagoChicago ILIL

Rule 4: Make Primary KeysRule 4: Make Primary KeysShort and StableShort and Stable

Primary Keys should be short because Primary Keys should be short because they are used for searching through they are used for searching through records and identifying datarecords and identifying data

Primary Keys should be stable because Primary Keys should be stable because changes made to Primary Key data have changes made to Primary Key data have to be propagated to matching Foreign to be propagated to matching Foreign Keys Keys

Rule 5: Maintain Table RelevanceRule 5: Maintain Table RelevanceRule 6: Maintain Field IndependenceRule 6: Maintain Field Independence

These rule helps to achieveThese rule helps to achieveThird Normal FormThird Normal Form

Each of your tables should represent a Each of your tables should represent a single entity, that is, provide information on single entity, that is, provide information on a single subjecta single subject

The entity should be represented by a The entity should be represented by a primary keyprimary key

Rule 5: Maintain Table RelevanceRule 5: Maintain Table RelevanceRule 6: Maintain Field IndependenceRule 6: Maintain Field Independence

strFNamestrFName strLNamestrLName strCompanystrCompany strWebsitestrWebsite

IsabelleIsabelle RingingRinging Hollister IndustriesHollister Industries http://www.hollister.comhttp://www.hollister.com

AnitaAnita ManhattanManhattan Pinkerton SmithPinkerton Smith http://www.pinksmith.comhttp://www.pinksmith.com

HarryHarry ArmpitsArmpits Donovan CompanyDonovan Company http://www.donovan.orghttp://www.donovan.org

MonaMona LottLott Tyler FlynnTyler Flynn http://www.tylerflynn.comhttp://www.tylerflynn.com

strFNamestrFName strLNamestrLName

IsabelleIsabelle RingingRinging

AnitaAnita ManhattanManhattan

HarryHarry ArmpitsArmpits

MonaMona LottLott

strCompanystrCompany strWebsitestrWebsite

Hollister IndustriesHollister Industries http://www.hollister.comhttp://www.hollister.com

Pinkerton SmithPinkerton Smith http://www.pinksmith.comhttp://www.pinksmith.com

Donovan CompanyDonovan Company http://www.donovan.orghttp://www.donovan.org

Tyler FlynnTyler Flynn http://www.tylerflynn.comhttp://www.tylerflynn.com

strIDstrID

IR255IR255

AM892AM892

HA883HA883

ML556ML556

strCompanystrCompany

Hollister IndustriesHollister Industries

Pinkerton SmithPinkerton Smith

Donovan CompanyDonovan Company

Tyler FlynnTyler Flynn

Database Normalization Raymond Mark/Learn iT! Incorporated.

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Transcript of Database Normalization Raymond Mark/Learn iT! Incorporated.