1. Introduction to Databases—Topics
Information and Data
User needs
Organization for efficient storage and retrieval
Designing Database Systems
The Relational Data Model
Databases: Past and Future

2. Information and Data
We will think about information as being organized data
Organized to be meaningful to the user
Organized to be easily accessible for storage and retrieval
Organization adds value to the data
Lowers users' costs of perceiving the meaning of the data
Lowers costs of storing and retrieving the data

3. Is it meaningful to the user? Is the organization clear to the user?
Data to Information
Some Data
23.17
24.15
27.21
26.87
28.15
26.15
27.68
25.70
25.73
27.38
25.61
24.84
25.80
Is it meaningful to the user?
Is the organization clear to the user?
Is the data easy to retrieve?
What would we like to know about the data?

4. Data to Information (cont.)
Date
Close
6-May
23.17
6-Apr
24.15
6-Mar
27.21
6-Feb
26.87
6-Jan
28.15
5-Dec
26.15
5-Nov
27.68
5-Oct
25.70
5-Sep
25.73
5-Aug
27.38
5-Jul
25.61
5-Jun
24.84
5-May
25.80
Does this help?
What else would we like to know?

5. Data to Information (cont.)
What do we still want to know?
Data to Information (cont.)
What value does this presentation of the same data provide?

6. Data to Information (cont.)
Each presentation provided more information to the user
Raw values
Meaning of the values
Visual presentation of trends in the values
Each presentation took more effort and computer resources to prepare
But each presentation acted on the same raw input data

7. Data to Information (cont.)
Our last data point was May 5th 2006
How valuable will this data be in a week? In a month? In a year?
What will give our data/information continuous value?
Update data frequently (real time?)
Reduce the cost of updating the information
Reduce the cost of retrieving the updated information

8. Data to Information (cont.)
Information systems typically require a large up front investment to provide a stream of benefits or reduced costs in the future
Careful design seeks to
Provide maximum value by identifying user needs
Data
Presentation to match decision making task
Reduce operating costs
Automate tasks
Reduce user effort

9. Database Management Systems
Database management software manipulates and manages databases
Oracle, SQL Server, Access, DBII, etc.
Databases contain the data to be manipulated
One software instance can control several databases
Applications communicate with the data through the database software
Multiple applications can share the same or multiple databases
Users can (but usually shouldn’t) manipulate data directly through the database software

10. Database Management Systems (cont.)
The meaning of data is stored with the data
Data can be addressed by its name, rather than by its place in the data order
New data fields can be added without disrupting existing programs
Programs can be changed without disrupting existing data
Characteristics of the relational data model (and object oriented data models) overcome many other problems

11. Designing Database Systems
Database Analyst designs the database components to reflect the business requirements
Entities (tables)
Attributes (fields or columns)
Indices and keys
Relationships
Foreign keys
Business rules
Information Products (outputs)

12. Designing Database Systems (cont.)
Applications are designed to interact with the data
Systems Analysis (ISM 4113) identifies business transactions
Discrete business actions that use the data
Enroll a new customer
Record purchase of a product
Record hiring an employee
Note that transactions are expressed in terms of business activities, not data
See Project Milestone III

13. Designing Database Systems (cont.)
System Design Goals
Stored data reflects business needs
Storage efficiency
Minimum storage space
Minimum data redundancy
Data is stored, retrieved, and updated efficiently
Data is accurate
We will see that these goals conflict with each other
Design must make trade offs between goals
Watch for these themes throughout the course
Key Design Goal

14. The Relational Data Model
Data is stored in rectangular storage structures called tables
Each table stores data about only one kind of business entity
Data in one table is related to data in other tables by common fields (keys)

15. Each data element (field) is described in the database
Database Tables
Each data element (field) is described in the database
Each table contains information on one kind of entity
Member
Record Number
Last Name
First Name
Address 1
165
Johnson
Amelia
20 Castle Court
166
Evans
Barton
12896 Viscaino Road
167
Booker
Troy
110 West Gadsden Street
169
Periatt
Barry
709 Royal St.
170
Norbeck
Matthew
PSC 303 BOX 61
171
Futch
David
513 Morris Rd.
173
Tomson
Alan
3324 Mills Bayou Drive
174
West
Dan
P. O. Box 81
176
Hintz
Willis
506 Pilot Avenue
177
Gaskin
Jerry
715 Sunningdale Cove
Each table is rectangular

16. Table Relationships
Member
Data in one table is related to data in other tables by common fields (keys)
Record Number
Last Name
First Name
Address 1
165
Johnson
Amelia
20 Castle Court
166
Evans
Barton
12896 Viscaino Road
167
Booker
Troy
110 West Gadsden Street
169
Periatt
Barry
709 Royal St.
170
Norbeck
Matthew
PSC 303 BOX 61
171
Futch
David
513 Morris Rd.
173
Tomson
Alan
3324 Mills Bayou Drive
174
West
Dan
P. O. Box 81
176
Hintz
Willis
506 Pilot Avenue
177
Gaskin
Jerry
715 Sunningdale Cove
Guest
Number
Member Number
LName
FName 38
167
Booker
Donna 40
173
Tomson
Mary Anne 42
187
McCusker
Sandra 43
166
Neves
Andrea 44
190
Pogge
Karen 45
191
Gajewski
LuAnn 46
200
Altshuler
Kathi

17. Databases: Past and Future
Database developments have been characterized by:
New approaches to organizing and presenting data
Falling prices for powerful hardware
Networking to distribute data
Growth of the Internet to extend data beyond the organization's boundaries
New technologies for developing databases
New technologies for developing database-based application programs

18. Databases: Past and Future (cont.)
What have been effects on business practices that you have seen in your lifetimes?
What changes can you expect to see if past trends continue?
What business changes will new technological capabilities introduce?
What role do you expect to play in all of this? (And how much money do you expect to make doing it?)

19. What's Next
Overview of the process of designing databases for organizational needs
Information Requirements Analysis
Get your project team organized