Databases on the Web

							Introducing Databases
      on the Web



    Thursday, 11 October 2012
Why Databases and the Web?
 Greatly improves finding information
 Greatly improves managing information
  Remote updating possibilities
 Vast mass of information held on existing databases
  Legacy systems can be revitalised
 Multi-platform
 Examples:
  Car sales: www.autotrader.co.uk
  Movie Database: uk.imdb.com
Uses for Databases on the Web

Organisational information services
Web-based collection of information   www.yell.co.uk
Facilities booking & scheduling
Document management
Electronic commerce
Web site automation
                              www.amazon.co.uk
Using Databases and the Web

Two main methods, depending on:
  How interactive you want the service to be
  How frequently changes are made
The methods are:
  Static pages
  Dynamic pages
Static Web Pages
 Data kept in the database
 Pages generated and transferred to web server
 No further connection to database needed
 No database searches or updates possible via the
  web
 Why do it?
  Suitable if data changes infrequently
  Separates content from appearance
Static Web Pages
                                                            Database



 Client          Web server

          HTTP


                                  FTP / Floppy Disk etc.



          HTML
                                                           .html file(s)


                         HTML files transferred to web server
                         No further connection to database
Producing Static Pages
Static pages can be produced using special
 tools e.g.
  MS Access export facility
     Access 95 & 97 also has the "Publish to the Web" wizard
  Simple and quick to use
  Lacks flexibility of queries and layout
Simple programmer written code
  More complex - programming skills required
  Complete flexibility
Dynamic Web pages
 Data kept in the database
 Pages generated from database on the fly via an
  interface technology (e.g. ASP, PHP, ColdFusion)
 Database remains connected to web server
 Database searching and updates possible via the
  web
 Why do it?
  Suitable if data changes/updates frequently
  Gives end users more functionality
  Separates content from appearance
Dynamic Web Pages

                                          "Interface
 Client             Web server                                     Database
                                          Technology"
             HTTP




             HTML                 HTML


 Database connected to web server via an "interface technology"
 Pages created dynamically - "on the fly"
Producing Dynamic Web Pages
Web server proprietary solutions
   e.g. Microsoft ASP
Middleware tools
   e.g. Cold Fusion
Bespoke web server applications
  Often open source
  Typically using CGI, PHP, Perl etc
Terminology: SQL, ODBC etc
Information Management Issues
 Performance depends on:
  Operating system
  Database format
  Web server
  Amount of traffic/calls to database
  Hardware/Network speed
 Other considerations:
  Dynamic pages
      Caching implications
      Robot search engines
  Database security and access
  Data Protection rules
MS Access - Publish to the Web
 Export option from Access
  Access 97/95 also have "Publish to the Web" Wizard
 Can produce both static and dynamic pages
 Dynamic pages use Microsoft ASP
  Automatically produces code
 Limited control over output
 Can create simple queries (dynamic pages only)
References

MS-Access and the Web using ASP:
  http://support.microsoft.com/
   default.aspx?scid=/support/access/
   content/internet.asp
Macromedia Cold Fusion (was Allaire):
  www.macromedia.com/software/
   coldfusion/