designin internet sytem

7/31/2019 Designin Internet Sytem

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Chapter 14

Designing Distributed andInternet Systems

Modern Systems Analysisand Design

Fourth Edition



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Learning Objectives

Define key client/server, LAN, distributeddatabase, and middleware terms.

Distinguish between file server andclient/server environments.

Describe alternative distributed systemdesigns.

Describe standards for Internet-based systemdesign.

Describe options for ensuring Internet design

consistency. Describe site management issues. Describe issues related to managing online

data.



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Deliverables and Outcome

• A document that consolidatessystem design information:

– Description of each site

– Description of data usage for each site

– Description of business process foreach site

– Contrasts of alternative ISarchitectures for site, data andprocessing needs of each site



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Designing Internet Systems

• Most new system development focuses onInternet-base applications (for internalprocessing, business-to-business, andbusiness-to-consumer)

• Main design issues: – Standards – Separating content from display – Future evolution

– Site consistency – Site management – Online data management



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Standards for InternetDesign

• Internet design is simpler thanclient/server due to proliferation ofstandards

• Types of Standards: – Domain naming (BIND): a method for

translating domain names into InternetProtocol (IP) addresses

– Hypertext Transfer Protocol (HTTP): acommunication protocol for exchanging

information on the Internet – Hypertext Markup Language (HTML): the

standard language for representing content onthe Web via command tags



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Separating Content fromDisplay

• HTML has limitations due to formatorientation of tags

• eXtensible Markup Language (XML)

has been developed to separatecontent from display

• XML: an Internet authoring language

that allows designers to createcustomized tags that represent datatransmitted between applications



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Future Evolution

• Move from desktop PCs to thinclients

– Most processing and data storage

occurs on the server

• Use of wireless mobile devices

– Wireless Access Protocol (WAP): a

wireless version of HTTP – Wireless Markup Language (WML): a

wireless version of HTML



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Site Consistency

• Professionalism requires a consistentlook-and-feel across all pages of a Website

• Aids to consistency: – Cascading Style Sheets

• A set of style rules that tells a Web browser how topresent a document

– Extensible Style Language (XSL)• Specification for separating style from content whengenerating HTML documents



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Site Management Issues

• Customer Loyalty andTrustworthiness – Conveyed by

• Design quality

• Up-front disclosure

• Comprehensive, correct and currentcontent

• Connected to the rest of the Web

• Data security

• Personalization

• Customization



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Site Management Issues(cont.)

• Web Pages Must Live Forever – Customer Bookmarks

– Links from Other Sites

– Search Engine Referrals – Old Content Adds Value

• System Security vs. ease of use

– “Remember my password” – Use of cookies



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Online Data Management

• Context development – Method of understanding how a system fits

within the existing business activities and data

• Integration depth

– Measurement of how far a system penetratesinto the existing technology infrastructure

• Organizational breadth

– Measurement that tracks the core businessfunctions affected by a system



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Context, Breadth and Depth

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Online Transaction Processing(OLTP)

• Refers to immediate automatedresponses to the requests of users

• Designed to handle multipleconcurrent transactions

• Plays a large role in electroniccommerce applications

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Online Analytical Processing(OLAP)

• Refers to graphical software toolsthat provide complex analysis of datastored in a database.

• OLAP server is the chief component

• Good for time series and trendanalysis

• Enables user to “drill-down” into the

data



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Data Warehousing

• Collection of data for decision support

• Key features

– Subject-oriented: organized around key

subjects – Integrated: data are collected from many

operational systems and made to conform tostandards

– Time-variant: data contains a time dimension – Nonvolatile: data cannot be updated by users

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Steps in Building and Using a

Data Warehouse

• Extract data from various sourcesystem files and databases

• Transform, integrate, and load thedata

• Data warehouse is a read-onlyenvironment

• Users access via query languagesand analytical tools

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Data Warehouse Architectures

• Two-level – Data warehouse and decision support

environment

• Three-level

– Operational systems

– Enterprise data warehouse• Centralized, integrated data warehouse

• Control point and single source of all data made

available to end users – Data marts

• A data warehouse that is limited in scope basedupon aggregation and selection

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