Normalization Case Study and Theory

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Functional Dependencies

The value of one attribute in a table is determined entirely by the value of another attribute.

For example, the birthday of a Customer can be determined by the primary key of the Customer, in which record the birthday belongs. Here an Customer’s birthday depends on the Customer’s primary key.

Customer birthday (depends on) -> Customer ID

The notation X -> Y means if and only if each X value is associated with at most one Y value.

We can find the birthday of a Customer, thru the ID of the Customer. Using the ID, for a one to one relationship (that is one Customer has ONLY one birthday), we can find the only birthday of a Customer. Where as using the birthday, we might find ID’s of several Customers, since same birthday might belong to multiple persons.

Understanding First Three Normal Forms

First normal form sample:

1. Create atomic values, i.e. which can’t be broken down more.

Address: Location + City + State + Country

Should be formed with separate fields:

Address table: Address ID, Location, City, State, and Country.

2. Remove repetitive column groups.

Customer table: Customer ID, Customer Name, Address ID, Address ID

Should be formed as:

Customer table: Customer ID, Customer Name

Customer Address table: Customer ID, Address ID

Second normal form sample:

Remove partial dependency.

Order Item table: Order ID, Inventory Item ID, Inventory Item Sell Price, Inventory Item Sell Quantity

Should be formed as:

Order Item table: Order ID, Inventory Item ID, Inventory Item Sell Quantity

Inventory Item table: Inventory Item ID, Inventory Item Sell Price

Third normal form sample:

Move the non-keys to a separate table, which don’t depend on keys (or depends on non-key).

Sales Order table: Sales Order No, Date, Customer No, Customer Name

Should be formed as:

Customer table: Customer No, Customer Name

Sales Order table: Sales Order No, Date, Customer No

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Print | posted on Wednesday, February 6, 2008 6:06 PM

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# re: Normalization Case Study and Theory

left by adisallem at 2/16/2009 12:35 AM Gravatar
i want to teach me about normalization
and frequently asked questions of the topic

# re: Normalization Case Study and Theory

left by nitin at 3/5/2009 5:59 PM Gravatar
i need some case study base on normlisation.

# re: Normalization Case Study and Theory

left by atul dubey at 4/28/2009 10:47 AM Gravatar
sir i m mca student of pune university & i wnt slove case study on normalization up to 3 nf

pls help me !!!

# re: Normalization Case Study and Theory

left by amber at 12/2/2009 4:07 AM Gravatar
plz give me solved examples of normalization

# re: Normalization Case Study and Theory

left by komal at 12/20/2009 4:55 AM Gravatar
sir plz give me solved example of normalization up to 3 nf but in tabler format

# re: Normalization Case Study and Theory

left by Aarti at 4/13/2010 1:54 AM Gravatar
sir pls give me solved case study on normalization upto 3nf.

# re: Normalization Case Study and Theory

left by usman saeed at 5/3/2010 3:39 AM Gravatar
sir i m stdudent of mit.db offer to us. sir plz help me coz i m new in db and normaliztion is very difficult

# re: Normalization Case Study and Theory

left by Asifhanif at 9/18/2010 11:24 PM Gravatar
sir i am a student of miom i cant understand db its new for me plz normalization in tabuler form upto 3 nf send me thanks

# re: Normalization Case Study and Theory

left by vishranti gharge at 3/24/2011 6:14 PM Gravatar
sir i want solved case study of normalization up to 3nf
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