ba471 management information systems databases. database fundamentals once upon a time, there were...
TRANSCRIPT
BA471Management InformationSystems
Databases
Database Fundamentals
Once upon a time, there were files Containing data “Flat files” not databases
Enter data
Enter data
Enter data
OrderSystem
Orders
BillingSystem
InventorySystem
Bills
Reports
Database Fundamentals
Systems needed each other’s data Order data needed for bills Qty data needed for orders … etc.
Enter data
Enter data
Enter data
orders
custs
qty
OrderSystem
Orders
BillingSystem
InventorySystem
Bills
Reports
Database Fundamentals
So every night, data that needed to be shared had to be copied from one system to another.
What a waste of time and resources, not to mention ….redundant!
OrderInfo
CustInfo
QtyInfotransfer transfer
OrderInfo
CustInfo
OrderInfo
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 Minimizes redundancy Treats data as an “asset” Standardizes data “One version of the truth”
Database Fundamentals
Problem?
CUSTOMER
Cust. Sat.System Sales
System
BillingSystem
People
OrderSystem
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
Customer
AccountAccount
Type
Billing cycle
owns
has
follows
Database Fundamentals
Your role in Data Modeling SME Requirements analysis Data definitions
Database Fundamentals
In-class exercise: Western All Around Pets, Inc.
Database Fundamentals
WesternAll-Around Pets Pres & CEO
COO CIO
Mgr ExoticPets
Controller
Mgr DomesticPets
InventoryData
Supervisor
BusinessAnalysts
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 Errors at data entry Software-introduced errors Deterioration over time Sabotage Honest mistakes