Download Week05-BUAD283-XlmA

Management Information Systems
for the Information Age
Extended Learning Module A:
Designing Databases and
Entity-Relationship Diagramming
Relational Database Theory & Practice
Database Terminology 1/4
What Is a Database?
A collection of related information, such as a
company’s accounting data
A database is comprised of one or more tables
Textbook Table
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Title
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Course Table
Course ID Title Credits Lecture Hours Lab Hours
XLM A: Designing Relational Databases
Slide 2
Database Terminology 2/4
What Is a Table?
Primary object for collecting and storing data
Tables are comprised of records, which are
organized into rows similar to an electronic
spreadsheet
Textbook Table
ISBN
Title
Author
Publisher Price
XLM A: Designing Relational Databases
Course ID
Slide 3
Database Terminology 3/4
What Is a Record?
An individual and complete entry in a table (for
example, a person’s name, address, and phone)
Records are comprised of fields, which are the
columns of information in a table
Each record is uniquely identified by a primary
key field (for example, an ID number or ISBN)
Textbook Table
ISBN
Title
Author
Publisher Price
0-6190-04430-6MS Access 2000
Adamski, Finnegan,
CourseHommel
Technology
XLM A: Designing Relational Databases
Course ID
75 BuAd 237
Slide 4
Database Terminology 4/4
What Is a Field?
Column of information that holds a single and
identifiable piece of data for a record, such as
ID, Surname, Given, Address, City, Province…
When the primary key field from another table is
included, it is referred to as a foreign key field
Primary Key
Foreign Key
Textbook Table
ISBN
Title
Author
Publisher Price
0-6190-04430-6MS Access 2000
Adamski, Finnegan,
CourseHommel
Technology
XLM A: Designing Relational Databases
Course ID
75 BuAd 237
Slide 5
Databases and Relationships 1/2
Tables are related through a common field
that appears in both tables
Textbook Table
ISBN
Title
Author
Publisher Price
Course ID
Course Table
Course ID Title Credits Lecture Hours Lab Hours
XLM A: Designing Relational Databases
Slide 6
Databases and Relationships 2/2
Related tables avoid data redundancy and
make tables easier to maintain
Textbook Table
ISBN
Title
Author
Publisher Price
0-6190-04430-6MS Access 2000
Adamski, Finnegan,
CourseHommel
Technology
Course Table
Course ID Title
BuAd 237
Course ID
75 BuAd 237
Credits Lecture Hours Lab Hours
Computer Softw are III 3
2
XLM A: Designing Relational Databases
2
Slide 7
Designing a Database 1/3
Normalization
Each data item should
be stored in a single
location
You normalize data by
dividing fields into
logical groupings of
related tables
Relational design should
attempt to minimize the
incidence of empty data
fields in a table
XLM A: Designing Relational Databases
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Designing a Database 2/3
Strive for the following design characteristics:
Each table represents an identifiable subject or topic
Each record stores data for one subject or topic only
Each field stores a single piece of data for a record
Assign a primary key field that uniquely identifies a record
Relate tables based on common fields and values
XLM A: Designing Relational Databases
Slide 9
Designing a Database 3/3
XLM A: Designing Relational Databases
Slide 10
Types of Relationships 1/3
One-to-One Relationship
A single record in table A relates to a single record in table
B, and vice versa
Used when you want to separate data from a main table,
perhaps for security reasons
Notice that the primary key fields are identical
XLM A: Designing Relational Databases
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Types of Relationships 2/3
One-to-Many Relationship
A single record in table A can be related to one or more
records in table B, but a single record in table B is related
to only one record in table A
Often referred to as a parent-child relationship
XLM A: Designing Relational Databases
Slide 12
Types of Relationships 3/3
Many-to-Many Relationship
A single record in table A can be related to one or more
records in table B, and a single record in table B can be
related to one or more records in table A
A third linking table, also called a join or junction table, is
used to negotiate the connection by storing primary keys
from both tables for a composite or compound key
XLM A: Designing Relational Databases
Slide 13
XLM A: Textbook Definitions
Database
A collection of information that you organize
and access according to the logical structure
of that information.
Relational database
Uses a series of logically related twodimensional tables or files to store
information in the form of a database.
XLM A: Designing Relational Databases
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XLM A: Steps in Designing a Database
1. Defining entity classes and primary keys
2. Defining relationships among entity classes
3. Defining information (fields) for each
relation (table)
4. Using a data definition language to create
your database
XLM A: Designing Relational Databases
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Step 1: Entity Classes and Primary Keys
Entity Class = a table; a concept or subject
Primary Key = a field that contains
information that uniquely identifies a record
Instance = a record; an occurrence of an
entity class that can be uniquely described
Identify business rules and define integrity
constraints
Start at the reports (output) and work
backwards (input)
XLM A: Designing Relational Databases
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Step 2: Relationships
Review business rules in order to verbally
describe the relationship between tables
Once the relationship has been established,
you must then determine the numerical
nature of the relationship, referred to as
minimum and maximum cardinalities
Normalize the database to ensure that the
relational structure can be implemented as a
series of two-dimensional relations (tables)
XLM A: Designing Relational Databases
Slide 17
Step 2: Rules of Normalization
1. Eliminate repeating groups or many-tomany relationships using an intersection
relation (join or junction tables)
2. Ensure that each field in a relation depends
only on the primary key for that relation
3. Remove all derived fields from the relations
XLM A: Designing Relational Databases
Slide 18
Step 2: E-R Diagramming
Creating an intersection relation to solve for a
many-to-many relationship using E-R Diagramming
XLM A: Designing Relational Databases
Slide 19
Step 3: Fields
Data Dictionary:
Ensure that the
information is in
the correct
relation/table
The information
should not be able
to be derived from
other data (unless
performance is an
issue)
XLM A: Designing Relational Databases
Slide 20
Step 4: Data Definition Language
Data Definition Language
Data definition language is part of the
database management system (DBMS)
Database Management System (DBMS)
DBMS helps you specify the logical
organization for a database and maintain
the information within the database
XLM A: Designing Relational Databases
Slide 21
Concluding Focus
Review the Student Learning Outcomes
summary in Chapter 3 and XLM A for
textbook-specific terminology
Know how to reproduce the E-R diagrams in
the text for simple database applications
Study this chapter (XLM A) thoroughly, as it
serves as a basis for the upcoming projects
XLM A: Designing Relational Databases
Slide 22