Definitions

Data - Facts, text, graphics, images, sound, and video segments that have meaning in the users’ environment

Information - Data that have been processed in such a way as to increase the knowledge of the person who uses the data

Metadata - Data that describe the properties or characteristics of other data

Database - A computerized orderly collection of logically related data

5 types of databases (Table 1-4)

• Personal - support one user
• Workgroup - support < 25 users
• Department - support a functional unit within a company
• Enterprise - support the entire organization
• Internet - universal access

Components of a database system (Fig. 1-10)

Data	Data definitions Data occurrences
Users	Data administrators System developers End users
Software	CASE tool DBMS Application programs User interface
Hardware	Storage or Repository Processor

Traditional file processing (Table 1-2)

• Data dependence
• Data duplication/redundancy
• Data isolation
• Data incompatibility
• Data inconsistency

Database processing (Table 1-5)

• Data independence
• Data sharing
• Data consistency
• Data standardization
• Data accessibility
• Data security??

Milestones in database processing (Fig. 1-11)

Era	Milestone	Contributions
1960s	Organizational transaction processing	Data volume  Data standard
1970s	Hierarchical (IMS) & Network (IDS) database model	Concurrency  Efficiency  Reliability
1980s	Relational database model	PCs  Popularity  Intuitive Ease of use
Mid 1980s	Client-Server database	Connectivity
Late 1980s	Distributed databases	Flexibility
Early 1990s	Object-oriented database	Reusability
1990s	Multimedia/Network databases	Accessibility  Pictures, sounds, movies, animations

Database analysis & design/development-- specifying a comprehensive organizational database structure to provide flexible, timely, and secure access to the right data so as to enhance organizational productivity

Evolution of database analysis & design

• Function-drive approach -- focusing on activities performed within an organization (information requests consolidating)
• Data-driven approach -- focusing on data and their properties (information needs understanding)
• Strategy-driven approach -- focusing on aligning information technology with business strategies (strategic data planning)

Phases in strategic data planning (Table 2-1)  

Phases	Goal	Elements
Strategic factor identification (Table 2-2)	To develop a context for database development	goals  critical success factors  problem areas
Corporate object identification (Table 2-3)	To define the scope for database development	organizational units  organizational locations  business functions  data categories  data handling procedures and applications
Enterprise model development	To create an overall picture/explanation of organizational data	functional decomposition for each business function (Fig. 2-2)  enterprise data model (Fig. 2-1)  planning matrixes (Fig. 2-3)

Database development strategy

Strategy	Description	Strength
Top-down	general à specific Strategic goals  Information requirements  System needs	· Global perspective  · Consistency  · Maintainability
Bottom-up	specific à general System needs  Requirement specifications	· Fast  · Less risky

Database development activities (Figure 2-5)

• Enterprise modeling à need? scope?
• Conceptual modeling à general understanding of database requirements
• Logical design à well structured data specifications
• Physical design à programs, hardware, operating systems, network, access mechanism, etc.
• Implementation à write, test, install database processing programs
• Maintenance à meet changing business conditions, correct errors, improve processing speed, ...

Outputs from database development

Database schema	conceptual  external/user view  physical/internal
Database applications	forms  queries  reports  menus  programs