The nature of good design

Design is the process of describing, organizing and structuring system components at architectural design level and detained design level.

Design: convert functional models from analysis into models that represent the solution.
1. focus on technical issues (language,software,hardware)
2. requires less user involvement that analysis

Design phase activities:

1. design and integrate the network
2. design application architecture
3. design the user interface ( how user interact with the system)
4. design the system interface (enable system to share and exchange information)
5. design and integrate the database (system analysis model to create physical database model)

6. design and integrate the system control ( controls are need for all the other design activities)

a. user interface - limit access to authorized users
b. system interface - protect from other systems
c. application architecture - record systems
d. database - protect from software/hardware failure
e. network - protect communication

Deployment environment - bridges analysis and design
hardware, system software, networking

Network design:

Internet: global collection of networks that use TCP/IP networking protocols
Intranets: private networks using same TCP/IP protocol as the Internet
Extranets: intranet has been extended outside the organization.

Application architecture: consists of standards and tools used in an organization

Client - server architecture:

Server - manage information system resources or provides well defined services for client
Client - communication with server or request resources or services.

Three layer client - server architecture:

Data layer - manages stored data in database
Business logic layer - implements rules and procedures of business processing.
Vies layer - accepts user input and formats and displays processing results.