Transcript IS 441 : DATABASE

Chapter 1:
The Database Environment and
Development Process
Essentials of Database Management
Jeffrey A. Hoffer, Heikki Topi, V. Ramesh
Copyright © 2014 Pearson Education, Inc.
1
Basic DB Terms
 Data: Meaningful facts, text, graphics, images,
sound, video segments
 A collection of individual responses from a marketing
research
 Information: Data processed to be useful in decision
making
 Pattern of geographical buying habit based on analysis of a
marketing research
 Metadata: Data that describes data
2
Data in Context
Large volume of facts, difficult to interpret / make decisions
3
Information
Useful for decision making / interpretation
4
Metadata
Descriptions of the properties or characteristics of the data,
including data types, field sizes, allowable values, and
documentation (Data Dictionary)
5
Universal Database Systems
Application
#1
Application
#2
DBMS
Database
containing
centralized
shared data
Application
#3
6
Database Systems




Collection of electronic data
Central repository of shared data
Stored in a standardized, convenient form.
Requires a Database Management System (DBMS)
7
Type of DB Models





File processing system (traditional)
Hierarchical
Network
Relational
Object-relational
8
Relational Database
 A relational database is a collection of tables that


are related to one another based on a common
field.
A common field is called a primary key(s).
 unique identifier in data model
When the primary key of one table is represented in
a second table to form a relationship, it is called a
foreign key.
9
Relational Database
A schematic diagram of a relational database (a) and a sample part of a
relational database showing different tables (b)
10
Relating Tables Using a Common Field
The primary key in the
Employer table (EmployerID) is
the common field that relates
this table to the Position table.
PositionID is the primary key in
the Position table. The EmployerID
field is a foreign key in this table.
Primary keys can only have one
occurrence in a table. Foreign keys
may have multiple occurrences.
11
Relational Database
 Advantages
 Easier database design, implementation,
management, and use
 Ad hoc query capability with SQL
 Powerful database management system
12
DATABASE MODEL
Hierarchical
Network
Relational
Object-Relational
PRODUCT
Focus
IMS
Ramis
ADABAS
Image
Access
DB2
dBASE V
EDA/SQL
FoxPro
Ingres
NOMAD
Oracle
Paradox
Rbase
SQL/DS
SQL Server
Sybase
ObjectStore
Universal
Server
Illustra
VENDOR
Information Builders International
IBM
Online Software International
Software AG of North America
Hewlett-Packard
Microsoft
IBM
Borland International
Information Builders International
Microsoft
Ask Group
Must Software International
Oracle
Borland International
Microrim
IBM
Microsoft
Sybase
Object Design
Informix
HARDWARE
Mainframe/PC
Mainframe
Mainframe
Mainframe
Mainframe
PC
Mainframe
PC
PC
PC
PC
Mainframe/PC
Mainframe/PC
PC
PC
Mainframe
PC
PC
PC
PC
Informix
PC
13
Database Applications
 Personal Database – standalone desktop



database
Workgroup Database – local area network
(<25 users)
Department Database – local area network
(25-100 users)
Enterprise Database – wide-area network
(hundreds or thousands of users)
14
Data Warehouse
Collection of historic… NOT current data…
15
Data Mining
• Help to find hidden patterns and relationships
in large databases to predict future behavior
– “If a house is purchased, then new refrigerator will
be purchased within two weeks 65% of the time.”
16
Components of the DB Environment
17
Components of the DB Environment
 CASE Tools – computer-aided software engineering
 Repository (data dictionary) – centralized storehouse of metadata
 Database Management System (DBMS) – software for managing the






database
Database – storage of the data
Application Programs – software using the data
User Interface – text and graphical displays to users
Database Administrators (DBA) – personnel responsible for
maintaining the database
System Developers – personnel responsible for designing databases
and software
End Users – people who use the applications and databases
18
Database Development Process
Feasibility Study of
Project
Purpose – preliminary understanding
Deliverable –request for project
Requirement Analysis
Conceptual Design
Logical Design
- Is the project worth looking at ?
- Is the DB system worth building?
Physical Design
Implementation
Maintenance
19
Database Development Process
Feasibility Study of
Project
Requirement Analysis
Purpose – state business situation and possible
solution
Deliverable –decomposed requirements
Conceptual Design
Logical Design
• What do users need and want
from the new system?
• What the new system must do
Physical Design
Implementation
Maintenance
20
Database Development Process
Purpose –thorough analysis
Deliverable – conceptual data model
Feasibility Study of
Project
Requirement Analysis
Conceptual Design
Logical Design
conceptual data model
- next slide
- example model from the web page
Physical Design
Implementation
Maintenance
21
Conceptual Data Model
22
Database Development Process
Feasibility Study of
Project
Purpose –information requirements structure
Deliverable – logical database design
Requirement Analysis
Conceptual Design
1.
Hierarchical DB
2.
Network DB
3.
Relational DB
4.
Object Oriented
Logical Design
Physical Design
Implementation
Maintenance
23
Database Development Process
Purpose –develop technology specs
Deliverable – program/data
structures, DB technology
purchases…
Feasibility Study of
Project
Requirement Analysis
Conceptual Design
Logical Design
• Define physical organization of data
Physical Design
Implementation
Maintenance
24
Database Development Process
Purpose – testing, training,
debugging, installation, documenting
Deliverable – operational programs,
documentation, training materials
Feasibility Study of
Project
Requirement Analysis
Conceptual Design
Logical Design
Physical Design
Implementation
Maintenance
25
Database Development Process
Feasibility Study of
Project
Purpose –monitor, repair, enhance
Deliverable – periodic audits
Requirement Analysis
Conceptual Design
Logical Design
Physical Design
Implementation
Maintenance
26
DB Development Schedule
Gantt Chart shows time estimates of tasks
27
DB Development Schedule …
PERT Chart shows dependencies between tasks
28
Incremental Commitment
in DB Development
 Project is reviewed at the end of each development
phase
 Re-justify the process under the light of new requirements
and available resources
 Renew commitment of stakeholders
 Continue / Revise Scope / Cancel
29