DBS211 Lab 09–Normalization solution




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• Students create the Un-normalized Form (UNF) relation from a user view.
• Students identify a Multi-valued Dependency(a.k.a. Repeating Group )
• Students create the First Normal Form (1NF) relation from the UNF.

Only submit the last section, however it is extremely important that you you’re your way through it first.
Save your lab file as a PDF file. You need to submit a single PDF file for this lab.
YOUR NAME AND STUDENT ID MUST BE IN THE PDF document or you will receive a mark of ZERO.
The name of the file must be as follow:
Definition: Normalization is the process of assigning attributes to relations in such a way that data redundancies are reduced or eliminated.
Definition: User Views can be individual descriptions, reports, forms, or lists of data that are required to support the operations of a particular database user.
Definition: Unnormalized form (UNF) is a relation that contains one or more Multi-valued Dependencies.

Definition:AMulti-valued Dependencyis an attribute or collection of attributes within a relation that has multiple values for a single value of the primary key for that relation.
Definition: A relation is in 1NF if it does not contain any multi-valued dependencies.

Step 1: Create UNF Relation from a User View. The goal here is to create a single relation for the data found in the user view. The method used is:
• Examine the user view
• Identify all attributes
• Describe the user view using DBDL

Here is an example of a user view. This reports lists the customers of the Premiere Corporation.
Premiere Corporation Customer List
CustNo Name Street City State ZipCode SalesRepNo
124 Sally Adams 482 Oak Lansing MI 49224 03
256 Ann Samuels 215 Pete Grant MI 49219 06
311 Don Charles 48 College Ira MI 49034 12
315 Tom Daniels 914 Cherry Kent MI 48391 06
405 Al Williams 519 Watson Grant MI 49219 12
412 Sally Adams 16 Elm Lansin MI 49224 03
522 Mary Nelson 108 Pine Ada MI 49441 12

A. Examine the user view: As you examine this report, you can see that it contains a title, a line of column headings and the body of the report. Each line in the body of the report contains data about a particular customer. For example we can see that in the first line of the body of the report, there is data about Customer 124. This customer’s name is Sally Adams and she lives at 482 Oak in Lansing, Michigan (MI). The Sales Representative who calls on Sally Adams is Sales Rep Number 03.
B. Identify all attributes: The attributes (or characteristics) of a User View can often be found by simply looking at the column headings. In our Customer Report we see that we have the following attributes: Customer Number, Customer Name, Street, City, State, Zip Code and Sales Representative Number.
C. Describe the relation using DBDL: Database Design Language (DBDL) is a standardized way of describing relations of a relational database. You describe a relation by:
a. Choose an appropriate name for the relation. We chose to name our relation CUSTOMER because each line in the report describes customer data.
b. List the attributes you found in the user view inside square brackets, giving each attribute a suitable attribute name. Note: calculated fields or derived fields should not be included in the DBDL
c. Determine which attribute would be suitable as a primary key and underline that attribute.
The DBDL for the relation resulting from our Customer user view would look as follows:

CUSTOMER [ CustNo, CustName, CustStreet, CustCity, CustSt, CustZip, CustRep ]

Now you try it. Examine the following report:

Premiere Corporation Parts List

Part Number Part Description Qnty On Hand Class Warehouse
On Hand Price
AX12 Iron 104 HW 3 24.95
AZ52 Dartboard 20 SG 2 12.95
BA74 Basketball 40 SG 1 29.95
BH22 Cornpopper 95 HW 3 24.95
BT04 GasGrill 11 AP 2 149.99
BZ66 Washer 52 AP 3 399.99
CA14 Griddle 78 HW 3 39.99
CB03 Bike 44 SG 1 299.99
CX11 Blender 112 HW 3 22.95
CZ81 Treadmill 68 SG 2 349.95

What type of data does each line in the report represent? _________________________________________________________________________


What attributes can you identify from the user view?

________________________________ ________________________________

________________________________ ________________________________

________________________________ ________________________________

What would be a suitable name for the UNF relation? ___________________________

Which attribute would be suitable as a primary key? ___________________________

Describe the UNF relation using DBDL:


Step 2: Recognize Multi-valued Dependencies.

For example, looking at the following User View, we see that for each Customer number, it is possible to have multiple values for the order number and order date attributes. Therefore the order number and date are a multi-valued dependency.

Premiere Corporation Customer Orders

Customer Number Name Order Number Order Date
124 Sally Adam 12489 2016-09-02
12500 2016-09-05
256 Ann Samuels 12495 2016-09-04
311 Don Charles 12491 2016-09-02
315 Tom Daniels 12494 2016-09-04
522 Mary Nelson 12498 2016-09-05
12504 2016-09-05

Identify multi-valued dependencies in DBDL by placing brackets around them. For example the DBDL for this User View would look like this:

CUSTOMER [ CustNo, CustName, (OrderNum, OrderDate) ]

Notice the brackets around the OrderNum and Orderdate attributes. This quickly and easily identifies a multi-valued dependency to someone who is reading the DBDL.

Common Mistake: A common mistake is to incorrectly identify repeating data as a multi-valued dependency. For example, the previous report could also have been printed in the following way:

Premiere Corporation Customer Orders

Customer Number Name Order Number Order Date
124 Sally Adam 12489 2016-09-02
124 Sally Adam 12500 2016-09-05
256 Ann Samuels 12495 2016-09-04
311 Don Charles 12491 2016-09-02
315 Tom Daniels 12494 2016-09-04
522 Mary Nelson 12498 2016-09-05
522 Mary Nelson 12504 2016-09-05

The fact that the Customer Number and Name for Sally Adams and Mary Nelson have been repeated on multiple lines does not make Customer Number and Name a multi-valued dependency! You should still identify that for one customer number, there are multiple values for the order number and date. Note that this does not mean that EVERY customer number will have multiple order numbers, just that this user view shows that it is possible for some customer numbers to have multiple values for Order Number and Date. The Multi-valued Dependency must be identified in the DBDL. Note also that it is possible to have more than 1 multi-valued dependency.

Step 3: Create 1NF relations from UNF.

Therefore, the process of taking a relation from UNF to 1NF, involves resolving the multi-valued dependencies.

– Choose a primary key for the multi-valued dependency.
– Identify the primary key of the multi-valued dependency by underlining it or writing (PK) .
– Rewrite the DBDL by removing the parenthesis and concatenating the original primary key with the primary key of the multi-valued dependency.
– Rewrite the DBDL with the two-part Primary Key and include all the non-key attributes.

For example, using our previous report from part B, we had the following:

UNF: Customer [ CustNo, CustName, ( OrderNum, OrderDate ) ]

A. Choose a primary key for the repeating group: OrderNum would make a suitable primary key for the repeating group as it uniquely identifies the data in the repeating group.

B. Rewrite the DBDL by removing the parenthesis and concatenating the original entity name with the entity name of the multi-valued dependency.

CustOrder [ CustNo, OrderNum, CustName, OrderDate ]

NOTE: If we start with a relation that does not contain any multi-valued dependencies, it is already in 1NF.

Last Section:
Lab 09 Submission:

For the following User View, determine the UNF and the 1NF and hand in this page only to your instructor.

Premiere Corporation Order Detail Report

Order Number Order Date Cust number Part Number Part Desc Number Ordered Quoted Price Total
12489 2016-09-02 124 AX12 Iron 11 14.95 164.45
12491 2016-09-02 311 BT04 GasGrill 1 149.99 149.99
BZ66 Washer 2 399.99 799.98
12494 2016-09-04 315 CB03 Bike 4 279.99 1,119.96
12495 2016-09-04 256 CX11 Blender 2 22.95 45.90
12498 2016-09-05 522 AZ52 Dartboard 2 12.95 25.90
BA74 Basketball 4 24.95 99.80
12500 2016-09-05 124 BT04 GasGrill 3 149.99 449.97
12504 2016-09-05 522 CZ81 Treadmill 2 325.99 651.98