BIS 245 Week 5 Lab – ER Diagram and ER Matrix

A. Lab # : BSBA BIS 245A-5A

B. Lab 5A of 7 : Database design using Visio, and based on data requirements

and business rules focusing on normalizing data to third normal form.

C. Lab Overview–Scenario/Summary:

TCO(s):

2. Given a situation containing entities, business rules, and data requirements,

create the conceptual model of the database using a database modeling tool.

Scenario:

You have been asked to create a database model using the MS Visio Database

Model Diagram Template. The purpose of this lab is to provide experience

normalizing the database to third normal form based on limited instructions, data

requirements, and associated business rules.

Upon completing this lab, you will be able to

1. create a new Visio file for database design; and

2. using the data requirements and the business rules provided, develop a

conceptual model (ERD), including attribute data types and required field

lengths.

D. Deliverables

Section Deliverable Points

Step 1 YourName_Lab5A_ERMatrix.docx

Step 3 YourNameLab5A.vsd (Visio Diagram)

E. Lab Steps

Preparation

1. Get the Lab5A_ERMatrix.docx document from Doc Sharing:

a. Download the Lab5A_ERMatrix document file from your course Doc

Sharing panel (Labs view), and Save the file to your local drive.

2. Using Citrix for MS Visio and/or MS Access

a. If you are using the Citrix remote lab, follow the login instructions

located in the iLab tab in Course Home.

3. Start MS Visio

a. Open Microsoft Office, Visio application, or

b. if you are using Citrix, click on Microsoft Office Applications folder

to start Visio. Page 2 of 5

Lab

Step 1: Identify the entities and relationships.

a. Over the past four weeks, you have created ERDs based on information

provided. This week, you will complete the ERD being sure to normalize it to

3NF (third normal form). Normalization is the systematic application of rules

designed to eliminate redundancy from the database. Data in previous weeks

was, to some extent, normalized for you. This week, it is not. An abbreviated

list of the data requirements follows.

College Scheduling Data Requirements

Student ID

Student First Name

Student Last Name

Course Code

Course Name

Course Description

Course Credit Hours

Course Time

Course Days

Instructor ID

Instructor First Name

Instructor Last Name

Room Number

Room Capacity

b. Open the Word file in the Week 5 Lab Materials, Lab5A_ERMatrix.docx

c. Save the Word file as YourName_Lab5A_ERMatrix.

d. An ER Matrix helps define both the entities and the relationships between the

entities. Using the partially completed ER Matrix below as a guide, complete

the matrix.

Hint: You should end up with four entities.

1. List each entity both across and down.

2. Determine whether a relationship exists between entities and define that

relationship with a verb phrase. (NOTE: The entity with the greatest

number of related entities is usually the center of the ER diagram.)

3. Identify minimum (Optional or Mandatory) and maximum (only one, or one

or more).Page 3 of 5

Student Course

Student none Enrolls in;

Mandatory

One or

more

Course Is taken by:

Optional

One or

more

none

e. Save the completed matrix to submit as part of your lab.

Step 2: Create the initial ERD based on the matrix.

a. Open a new blank Database Model Diagram in Visio. If you need assitance with

this, refer to the Week 1 Lab Instructions. Be sure that all options are set

consistent to those used in previous weeks so that you generate your model in

Crow’s Foot notation.

b. One of the issues in denormalized data is that it can result in many-to-many

relationships that are not compatible with the relational database. Visio does

not allow creation of a many-to-many relationship because of this

incompatibility. Therefore, for any many-to-many relationships in your data,

you will need to create two one-to-many relationships. See the example

below:Page 4 of 5

c. Based on the information from Step 1, create the initial ERD for the College

Scheduling database including the many-to-many relationships. If you need

assistance to create the entities, refer to labs from Weeks 1 and 2.

d. Assign the primary keys and attributes from the data requirements to the

proper entities.

e. Save the file as YourName_Lab5A.vsd.

Step 3: Normalize the database

a. While the initial ERD is accurate, if you design a database without deviating

from it, you will encounter problems. For example, a course is offered many

times. If you use the course code, for example BIS 245, as the primary key,

you will only be able to list the course once. There are three possible solutions.

1. Assign another primary key, such as an auto-number field, so that

the course can be listed multiple times. However, this is not

acceptable because it introduces redundancy rather than reducing it.

2. Use a composite primary key consisting of the Course Code and the

Section code. If you create a unique section code (EXAMPLE:

YearTerm_Section or 2010SpringA_A), then you can list the course

repeatedly. Again, this introduces redundancy, and is not an

acceptable solution.

3. Split the table to create two tables. TostayconsistentwithDeVry

terminology, create a second Section table. To ensure that a course is

not entered twice, you might modify the Section code to include the

course: BIS 245_2010SpringA_A. By consistently using this format,

you should not be able to duplicate the section, and can avoid a

complicated composite key. However, as the Section table will serve

as an associative entity, it is acceptable to borrow the primary keys of

theparenttables.

b. Open the Visio file from Step 2, and add a new page. Changethepagetabto

read Revised. Revise the initial ERD based on the following information.

1. A Course may exist without being offered. It exists in the catalog.

Courses are scheduled for a term and given a section. It is the

schedule course (Section) that students enroll in, that are scheduled

in rooms and assigned instructors.

2. A Student can exist without being enrolled in a course.

3. An Instructor can exist without being assigned to teach a course.

4. A Room can exist without being scheduled for a course.

c. Save the file with your revised ERD.Page 5 of 5

Lab 5A Final Deliverables

a. YourName_Lab5A_ERMatrix.docx  (Word Document) from Lab 5A Step 1

b. YourName_Lab5A.vsd (Visio Diagram) from Lab 5A Step 3.

Submit these files to the Week 5 iLabDropbox.