1/16 Overview - Andrew.cmu.edu
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Information Resources
Management
January 16, 2001
Agenda
Administrivia
Course Overview
Database Management Systems
(DBMSs)
Homework #1
Administrivia
Syllabus
Book
Homework
Web Page
Course Calendar
Eleven Homeworks
Approximately one per week
Exams
Midterm 1 - 2/20
Midterm 2 - 3/20
Final - TBA
Quizzes
Up to five
Overview – Perspective
Database Design and Implementation
“Business” Perspective
IT professional in an organization
Database Design
Relational Model
Database Modeling
Evaluation Tools
Normalization
Database Implementation
SQL (Structured Query Language)
Dependability, Reliability
Architecture
Distributed Databases
Database Management
Systems
Traditional File Processing Systems
Database
Comparison
Database Lifecycles
Database Management System
Functions
Traditional File Processing
System
Separate Files
Department
Business Function
Independent of Each Other
High Level of Program Dependence
Program contains file structure and
location
Example
Time Cards
Data
Entry
Trans
Trans
Sort by
Employee
#
Sorted by
Employee
#
Master
Update
Master
Report
Checks
New
Master
Data Abstraction (Views)
Physical/Internal
How data is stored
Logical/Conceptual
What is stored
View/External
What is used
(subset)
Traditional file processing prevents
this abstraction. Why?
Three Views of Data
External
(View)
Conceptual
(Logical)
Internal
(Physical)
Client
Customer
Designer
Database
Administrator
(DBA)
Programmer
Database
Administrator
(DBA)
Tech Support
What is Needed
Physical Independence
Logical Independence
Physical Independence
Physical layout and organization of data
can be changed without changing either
the overall logical structure of the data
or the application programs
Examples
Move data location
Move data to faster storage
Change indexing
Add a secondary key
Physical Independence
External
(View)
Conceptual
(Logical)
No Resulting
Change Here
Internal
(Physical)
Change Here
Logical Independence
Non-loss changes to the logical structure
can be made without changing application
programs or end-user views
Examples
Change format of a field (zip from 5 to 9)
Add a new data field
Add a new table
Divide a table into two
Logical Independence
External
(View)
No Resulting
Change Here
Conceptual
(Logical)
Change Here
Internal
(Physical)
Coordinating
Change Here
Database
organized collection of logically related
data
shared collection of interrelated data
designed to meet the informational needs
of multiple users
data is independent of program and user
views
data is stored with physical and logical
independence
Database Management
System (DBMS)
Software that facilitates the
implementation of the database concept
Comparison
(Traditional vs. Database)
Database Advantages/Traditional
Disadvantages
program-data dependence
duplication
data sharing
development times
program maintenance – ripple effects
flexibility
Comparison
(Traditional vs. Database)
Database Advantages/Traditional
Disadvantages
security
data integrity
data as corporate resource
Comparison
(Traditional vs. Database)
Traditional Advantages/Database
Disadvantages
size
complexity
cost
special hardware
impact of failure
recovery
Comparison
(Traditional vs. Database)
Traditional Advantages/Database
Disadvantages
additional personnel
conversion costs
organizational conflict
Database Lifecycle
1. Enterprise Modeling
2. Conceptual Data Modeling
3. Logical Database Design
4. Physical Database Design and
Creation
5. Database Implementation
6. Database Maintenance
People Involved
Systems analysts & designers
Database analysts & designers
Users
Programmers
Database Administrators (DBAs)
Networking experts
Other technical experts
Database Management
System Functions
data storage, retrieval and update
user-accessible catalog
transaction support
concurrency control
recovery services
authorization services
support for data communication
Database Management
System Functions
integrity services
types - character, number, etc.
internal validity
services to promote data independence
(logical and physical)
utility services
Database Applications
Personal
one user
Workgroup
small team - LAN connected
Department/Division
multiple teams and functions
Enterprise
entire organization
In-Class Exercise
Groups of 4
Introduce yourself
Identify a possible database of each
type
Pick a speaker
In-Class Exercise
Introduce yourself and group members
Give group’s example databases
personal
workgroup
department/division
enterprise
Personal Databases
Benefits
individualized
meet specific
needs
purchased
package
Drawbacks
limited to no data
sharing
replicated data
consolidation standardization
support
Workgroup Databases
Benefits
meet specific
needs
data shared
(across group)
customized
“views”
Drawbacks
data sharing
across groups
replicated data
security
not optimal for
individual
DBMS cost &
support
Department Databases
Benefits
meet (specific)
needs
data shared
Drawbacks
data sharing
replicated data
security
not optimal for
individual/group
performance
DBMS cost &
development
Enterprise Databases
Benefits
meet needs
data shared
“mineable”
consistent view to
customers
Drawbacks
size & complexity
security
cost & support
development
standards &
bureaucracy
distribution &
ownership
Best Database?
Personal?
Workgroup?
Department?
Enterprise?
Best Database?
Personal?
Workgroup?
Department?
Enterprise?
Combination of databases that meets the
needs of individuals, teams,
departments, and the company
Best Database?
To the individual, it’s a personal
database
To the team, it’s a workgroup database
To the department, it’s a department
database
To the CEO, it’s an enterprise database
(To the DBA, it’s a headache)
Homework #1
Data management recommendation
High-level, experience based
“glossy” vendor material
Show
alternatives
strengths/weaknesses of each
well-reasoned explanation