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Jim Janson
AgendaEvolution of software architectures3-tierUser interfacesApplication serversDatabases
In the beginning, there were mainframes…
Mainframe ArchitectureAdvantages
Simple deploymentSecure
DisadvantagesDumb terminals limited user interfaceAll work performed on server
Client-Server Architecture
Client-server ArchitectureAdvantages
Richer user interfacesProcessing off loaded to PCs
DisadvantagesMultiple copies of software; updates a problemOnly so much horse power on a PC
3-Tier Architecture
3-Tier ArchitectureTier 1: the client contains the presentation
logic “thin client”
Tier 2: application server provides the business processes logic and the data access.
Tier 3: the data server provides the business data.
3-Tier ArchitectureEasier to modify or replace any tier without
affecting the other tiers.
Separating the application and database functionality means better load balancing.
Adequate security policies can be enforced within the server tiers without hindering the clients.
Thin Client = Web BrowserUser interface displayed in a web browserTop web browsers:
Internet Explorer Firefox Safari Opera
Web BrowsersAll browsers interpret HTML and Javascript
Tools for Building Web PagesDreamweaverMicrosoft Expression WebPlus many free sites and tools
Extending the browserActive X Controls/Plug-insAbility to support more than just
HTML/JavascriptPopular extensions:
FlashJavaSilverlight
Some sites to look at:http://www.2advanced.comhttp://demo.northkingdom.com/ihuvudetpatoyota/in
dex_en.htmlhttp://www.stat.sc.edu/~west/javahtml/Histogram.h
tml
Middle tierTies client to dataWeb server
Serves web pages to browserBusiness logic Database access
Database ServerSeparate computer running database
softwarePopular databases
OracleSQL ServerMySQLPostgresSQL
What’s SQL?
DatabasesConsist of tables Each table has columns and rows (records)Each column has different attributes
UserId FirstName LastName Street City
1 Abby Wentworth 3 Park Place
Boston, MA
2 Pete Pierce 34 Glass Ave
Berlin, NH
3 Sam Adams 17 First St Fargo, ND
SQL create table USERS ( userid number(19,0) not null,
firstname varchar(30) , lastname varchar(30), street varchar(100), city varchar(40));
Storing InformationA table can store millions of records Don’t want to duplicate informationUse multiple tablesCommon information in a table
ScenarioTrack purchases at a web siteUser must create an accountUser logs in with account to purchase
Users Table
Purchases
UserId FirstName
LastName
Street City
1 Abby Wentworth
3 Park Place
Boston, MA
2 Pete Pierce 34 Glass Ave
Berlin, NH
3 Sam Adams 17 First St Fargo, ND
PurchaseId
Date Item Price UserId
4234 07/11/2009 Book 19.95 1
4235 09/04/2009 Wii 249.95 3
4236 10/21/2009 Rock Band 49.95 3
Data miningData mining is the process of extracting
patterns from data.Predict trends and behaviorsDiscover unknown patterns
Use in sales Google flu trends
http://www.google.org/flutrends/intl/en_us/