NORMALIZACIÓNprofwnegron.weebly.com/uploads/8/1/9/1/8191586/... · let’s look at this table: order_ number order_ date delivery_ date part_ number part_ amount part_ description

NORMALIZACIÓNPROF. WANDA I NEGRON RIOS

[email protected]

COPYRIGHT © 2016

mailto:[email protected]

USER VIEWS

• A user view can help us see what data

is collected and saved by a system

• Examples of user views:

• Input / Output Screens

• A report

• A form

• A table

Prof. Wanda I. Negrón Rios - Copyright © 2016 2

USER VIEWS

• It’s just one of many places to start to

determine which data your system

needs to collect, process, and store


LET’S LOOK AT THIS TABLE:

ORDER_

NUMBER

ORDER_

DATE

DELIVERY_

DATE

PART_

NUMBER

PART_

AMOUNT

PART_

DESCRIPTION

UNIT_

PRICE

VENDOR_

NUMBER

VENDOR_

NAME

VENDOR_

ADDRESS

11673 05/15/2013 05/29/2013 2396

1195

5893

3

4

1

Fan Belt

Oil Filter

Tail Lamp

$13.50

$5.75

$18.95

792

561

446

Acme

Harding

United

242 River St., Beacon, NY 10437

11 Oak Ave., Chadwick, NJ 07769

232 Hill Rd., Norwalk, CT 14876

11674 05/16/2013 05/30/2013 1195 1 Oil Filter $5.75 561 Harding 11 Oak Ave., Chadwick, NJ 07769

ORDER

Observe how for the first order, the first three fields would

have to be stored repeatedly for each part ordered.

This would mean repeating the same data three times.

This is inefficient use of data storage space.


CONVERT TO THIS FORMAT:

ORDER_

NUMBER

ORDER_

DATE

DELIVERY_

DATE

PART_

NUMBER

PART_

AMOUNT

PART_

DESCRIPTION

UNIT_

PRICE

VENDOR_

NUMBER

VENDOR_

NAME

VENDOR_

ADDRESS

11673 05/15/2013 05/29/2013 2396

1195

5893

3

4

1

Fan Belt

Oil Filter

Tail Lamp

$13.50

$5.75

$18.95

792

561

446

Acme

Harding

United





ORDER

ORDER (Order_Number, Order_Date, Delivery_Date,

Part_Number, Part_Amount, Part_Description,

Unit_Price, Vendor_Number, Vendor_Name,

Vendor_Address)


UNDERLINE THE PRIMARY KEY

ORDER_

NUMBER

ORDER_

DATE

DELIVERY_

DATE

PART_

NUMBER

PART_

AMOUNT

PART_

DESCRIPTION

UNIT_

PRICE

VENDOR_

NUMBER

VENDOR_

NAME

VENDOR_

ADDRESS

11673 05/15/2013 05/29/2013 2396

1195

5893

3

4

1

Fan Belt

Oil Filter

Tail Lamp

$13.50

$5.75

$18.95

792

561

446

Acme

Harding

United





ORDER


Part_Number, Part_Amount, Part_Description,


Vendor_Address)


INDICATE REPEATING GROUPS { }

ORDER_

NUMBER

ORDER_

DATE

DELIVERY_

DATE

PART_

NUMBER

PART_

AMOUNT

PART_

DESCRIPTION

UNIT_

PRICE

VENDOR_

NUMBER

VENDOR_

NAME

VENDOR_

ADDRESS

11673 05/15/2013 05/29/2013 2396

1195

5893

3

4

1

Fan Belt

Oil Filter

Tail Lamp

$13.50

$5.75

$18.95

792

561

446

Acme

Harding

United





ORDER


{Part_Number, Part_Amount, Part_Description,


Vendor_Address})


INDICATE REPEATING GROUPS { }

ORDER

(Order_number, Order_date, Delivery_date, {Part_number,

Part_amount, Part_description, Unit_price,Vendor_number,

Vendor_name, Vendor_address})


FIRST NORMAL FORM (1NF)

1. Remove the repeating group and make it a table

You will end up with two tables

ORDER (Order_number, Order_date, Delivery_date)

(Part_number, Part_amount, Part_description, Unit_price,

Vendor_number, Vendor_name, Vendor_address)


FIRST NORMAL FORM (1NF)HOW DO WE “TIE” THE TWO TABLES?



(Part_number, Part_amount, Part_description, Unit_price,


Answer: adding the Primary Key of the first table


FIRST NORMAL FORM (1NF)NOW YOUR TWO TABLES ARE CONNECTED



(Order_number, Part_number, Part_amount,

Part_description, Unit_price, Vendor_number, Vendor_name,

Vendor_address)

** The second table has a compound or concatenated key.


FIRST NORMAL FORM (1NF)NAME THE SECOND TABLE



ORDER-PART



Vendor_address)


FIRST NORMAL FORM (1NF)COMPOUND PRIMARY KEY


ORDER-PART



Vendor_address)



The new table (for the repeating group) will have:

• The Primary Key of the original table +

the fields from the repeating group

• The Primary Key will be a compound key* consisting of:

• The primary key of the original table +

the primary key of the repeating group

* Aka – Concatenated Key



• WAIT…

• What if the table has no repeating groups?

(see example below)

• Then you will say:

• “The table is already in 1NF because there are no

repeating groups”

EMPLOYEE

(Employee_Number, Employee_Name, Employee_Address,

Employee_Education)


SECOND NORMAL FORM (2NF)

• Remove Partial Dependencies

• This is applied to the table with the compound primary key

• All fields must be dependent on the primary key

(on the entire concatenated key)

• If you find fields that are only dependent on one part of

the compound key, take them out and make another table.

• Analyze each field


ORDER-PART

(Order_number, Part_number, Part_amount, Part_description, Unit_price,





• This is applied to the table with the compound primary key




ORDER-PART

(Order_number, Part_number, Part_amount, Part_description,

Unit_price, Vendor_number, Vendor_name, Vendor_address)




ORDER

(Order_number, Order_date, Delivery_date)

“Order” is already in 2NF because it contains no

partial dependencies






ORDER-PART


Part_description, Unit_price, Vendor_number,

Vendor_name, Vendor_address)



ORDER-PART


Part_description, Unit_price, Vendor_number,


• Split this table into two tables:

• One table with the fields that depend on the

entire concatenated key

• Another with the fields that depend on only one

part of the concatenated keyProf. Wanda I. Negrón Rios - Copyright © 2016 20


ORDER-PART

(Order_number, Part_number, Part_amount)

PART

(Part_number, Part_description, Unit_price,


Notice that the tables are connected through the

field Part_number.


SECOND NORMAL FORM (2NF)ALL TABLES

ORDER


ORDER-PART


PART




THIRD NORMAL FORM (3NF)

• Remove Transitive Dependencies

• Where there is a non-key field that is dependent

on another (both non-keys)

• Check all tables for transitive dependencies

ORDER


ORDER-PART


PART

(Part_number, Part_description, Unit_price, Vendor_number,





• Non-key field dependent on another non-key field

ORDER


“Order” is already in 3NF because it contains no

transitive dependencies





ORDER-PART


“Order-Part” is already in 3NF because it contains

no transitive dependencies





PART







PART





PART


Vendor_number)

VENDOR

(Vendor_number, Vendor_name, Vendor_address)




• Create a new table with the fields from the 2NF

table that depend on another nonkey field

• The primary key of this table will be the field

that the other(s) depend on

• Leave the primary key of the new table in the

original table

• It will be called a foreign key – identified by a

dashed underline


THIRD NORMAL FORM (3NF)LIST ALL YOUR TABLES

FINAL SOLUTIONORDER


ORDER-PART


PART

(Part_number, Part_description, Unit_price, Vendor_number)

VENDOR

(Vendor_number, Vendor_name, Vendor_address)


NOW WE PREPARE THE ERDS

• An Order contains one or many parts.

• A Part has only one description and unit price.

• A Part has only Vendor.



NOW WE PREPARE THE ERDS

VENDOR

PART

ORDER

ORDER-PART

conta

ins

has

Are

pa

rt o

f

Belongs to

sup

plie

s

Is s

upp

lied

by

Documents

NORMALIZACIÓNprofwnegron.weebly.com/uploads/8/1/9/1/8191586/... · let’s look at this table: order_ number order_ date delivery_ date part_ number part_ amount part_ description