1. ASP, Databases, and how to stomp project 3 Chris North cs3724: HCI

3. Presentations matthew jaswa, jason bower Vote: UI Hall of Fame/Shame?

4. Next Project 3: due Thurs Apr 25 Presentations: UI critique or HW2 results Next Tues: lawrence lauderdale, greg walker chris shirk, rick harris Next Thurs: michael young, eric tester craig sinning, darrin schmidt

5. Review WUI vs. GUI? * multiple users Out of sync between client & server * maintain state How does ASP help? * tracks users * Tracks state - session

6. Review examples of “client-server out of sync” problem? re-post problem Jump-in problem Browser cache Server crashes Lost messages, network problems, corrupted files Same user, multiple browser windows

7. Project 3 tools Developing: ftp://pid@infovis.cs.vt.eduftp://pid@infovis.cs.vt.edu Visual InterDev FrontPage Viewing: http://infovis.cs.vt.edu/pidhttp://infovis.cs.vt.edu/pid

8. Client-Server Sync Problems Re-post problem Form instance has unique id Store it in db Expires, get new fresh form Increment counter, per user

9. Client-Server Sync Problems Jump in too deep problem On a deep page, check for username? redirect Relaxed vs. gestapo Gestapo: test if source,dest page is possible connection

10. Client-Server Sync Problems Browser cache problem <% Response.Expires = -1 Response.Expiresabsolute = Now() - 2 Response.AddHeader "pragma","no-cache" Response.AddHeader "cache-control","private" Response.CacheControl = "no-cache" %> Random queryString: ” > ”

11. Consistent look-and-feel Banner Navigation bar Overview+detail Software maintenance nightmare? Server-side ‘include’ files: Put banner, nav bar in separate ‘include’ file: Can be used in.html files too

12. Data-Driven Websites Websites that provide access to: Lots o data Dynamic data Customized views of data E.g. ebay.com Scripts map data to html UI design, infovis principles Database html

13. Infovis and web pages Scrolling? Don’t have much better options Simple graphics Trick: red.gif = 1x1 pixel gif Item1 Item2 Item3 Item4 Item5 …

14. Databases Project3 database ODBC ActiveX Database Objects (ADO) Open database connection Query (SQL) Receive RecordSet Fields, values Fields Records movenext

15. Typical SQL Queries Get all records: SELECT field1,field2 FROM table SELECT * FROM table Sorting: SELECT * FROM table ORDER BY field1 Get certain records: SELECT * FROM table WHERE field1=value Adding a record INSERT INTO table(field1,field2) VALUES (value1,value2) Don’t muck with ID field

16. Project 3? Tools Client-server sync problems/solutions Databases