Transcript Database Fundamentals

BA471
Management Information
Systems
Databases
Database Fundamentals
 Once upon a time, there were files
 Containing data
 “Flat files” not databases
Enter data 

Order
System

Orders
Enter data 

Billing
System

Bills
Enter data 

Inventory
System
 Reports
Database Fundamentals
 Systems needed each other’s data
 Order data needed for bills
 Qty data needed for orders … etc.
Enter data 
orders
 System 
Order
Orders
Enter data 
custs
Billing
 System

Bills
Enter data 
qty
Reports
 Inventory
System 
Database Fundamentals
 So every night, data that needed to be shared
had to be copied from one system to another.
Order
Info

transfer

Cust
Info
Order
Info

transfer

Qty
Info
Cust
Info
Order
Info
What a waste of time and resources, not
to mention ….redundant!
Database Fundamentals
 A database is:
 A shared collection of data that is shared
and used for multiple purposes.
 Symbol =
Database Fundamentals
 A database consists of
 Tables
 Made up of
 Rows
 Columns
 That organize data so it’s usable by
people and software
Database Fundamentals
 Advantages of database approach


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
Minimizes redundancy
Treats data as an “asset”
Standardizes data
“One version of the truth”
Database Fundamentals
 Problem?
Order
System
CUSTOMER
Cust. Sat.
System
Sales
System
People
Billing
System
Database Fundamentals
 A DBMS is a group of programs that
interface between an actual
database
and a person
or a
PROGRAM
Database Fundamentals
 Examples of DBMS




SQL
MYSQL
DB2
Oracle
Database Fundamentals
 Applications are made up of
 Data in databases
 Processes in programs
 Programs change – a lot – but data is
stable
 Creating new applications: Start with the
data
 (Another database advantage is that you CAN
start with the data when designing new
applications.)
Database Fundamentals
 Step 1: Define & Analyze the data
 Entity: A person, place, thing or event
about which you want to capture data.
 Relationships: Between entities.
 Elements or Attributes: Characteristics of
entities
 Allowed values
Database Fundamentals
 Data Modeling – Designing the data
 A narrative & schematic model
 Defining entities, relationships,
elements, attributes
 Later, becomes a physical database
design
Database Fundamentals
Banking Account Data Model
Billing
cycle
Customer
follows
owns
Account
has
Account
Type
Database Fundamentals
 Your role in Data Modeling
 SME
 Requirements analysis
 Data definitions
Database Fundamentals
 In-class exercise:
Western All Around Pets, Inc.
Database Fundamentals
 Western
All-Around Pets
COO
Mgr Exotic
Pets
Mgr Domestic
Pets
Pres & CEO
CIO
Controller
Business
Analysts
Inventory
Data
Supervisor
Database Fundamentals
 Data modeling – next steps
 Create an ERD
 Relational model
 Forward engineer a physical database
(DDL)
 Schema
 Define the data
 Business definitions
 Metadata
 Domain
Database Fundamentals
 Data Quality issues
 Ways in which data quality can be
compromised



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Errors at data entry
Software-introduced errors
Deterioration over time
Sabotage
Honest mistakes