Devry BIS245 Week 5 Lab – ER Diagram and ER Matrix

BIS 245 Week
5 Lab – ER Diagram and ER Matrix
A. Lab # : BSBA BIS245A-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 BIS245, 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. To stay consistent with
DeVry
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: BIS245_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
the parent tables.
b. Open the Visio file from Step 2, and add a new page. Change the
page tab to
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 iLab Dropbox.
END OF LAB