The Web and Data Management

1
The Web and Data Management

• Experience is never limited, and it is never
  complete it is an immense sensibility, a kind of
  huge spider-web of the finest silken threads
  suspended in the chamber of consciousness, and
  catching every air-borne particle in its tissue.
• Henry James

2
New data management role

• Managing Web site data
• Linking databases to the Web
• Multimedia databases

3
Information presentation

• Information architecture
• The macro organization of information
• Information design
• The arrangement of information structures
• Information arts
• The arrangement of information elements on a page

4
Organization models
5
Navigation aids

• Signs let visitors know where they
• are
• can go
• Good examples are the London Underground and
  Paris Métro

6
The design process

• Architecture
• Outline the broad structure
• Use an outliner
• Design
• Clarify the form of each section
• Show linkages between pages
• Information arts
• Add the information elements to each page

7
The design process

• Consistency
• A consistent look and feel accelerates
  information finding
• A performance
• Web sites are expected to be entertaining as well
  as informative
• The Web site defines the firm for many
  stakeholders
• The shop window or building facade

8
Web site management

• Creating and maintaining HTML
• Use a special-purpose editor
• Managing a Web site
• Use a special-purpose tool such as Adobe GoLive

9
Site management
10
Site management

• Visual site management
• Automatic link changes
• Link checker
• Internal
• External
• Web site publishing

11
Some guidelines

• All images in one file
• Consistent naming
• Lowercase

12
Resource Description Framework

• We need a more precise description of what is on
  the Web
• Move the Web from machine-readable to
  machine-understandable.
• The RDF is a general framework for describing any
  Internet resource

13
Sample RDF

• ltrdfRDF xmlnsrdf"http//www.w3.org/1999/02/22-r
  df-syntax-ns"
• xmlnsdc"http//purl.org/dc/elements/1.0/"gt
  
• ltrdfDescription rdfabout"http//www.wiley.com
  /college/watson"
• dccreator"Richard T. Watson"
• dctitle"Data Management"
• dcdescription"Support for the 4th edition
  of Data Management Databases and Organizations
  by Richard T. Watson"
• dcdate"2003-07-01" /gt
• lt/rdfRDFgt

14
DBMS connectivity

• The Web browser is the interface of choice
• One-time installation
• Global
• Simple design is easy to learn
• A standard interface makes new applications
  easier to learn

15
Three-tier architecture
DBMS server
Web browser
DBMS server
Web server
Web browser
DBMS server
16
Options

• Common gateway interface (CGI)
• Does not scale well
• Proprietary Web server APIs
• Ties to vendors software
• ASP (active server pages)
• SSJS (server side JavaScript)
• Java servlets and JSP
• Java is difficult to learn

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PHP

• An open source server side scripting language
• A PHP application consists of HTML and PHP
  script, which are executed by the server before
  sending a page of HTML code to the browser
• Works with any browser
• Platform independent
• Versions are available for most operating systems
  and Web servers

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PHP

• Less network traffic because the browser has to
  send fewer commands to the server
• Simple interface to a DBMS
• Code cannot be seen by the browser user and thus
  security is high

19
Simple PHP scriptsimple.php

• lthtmlgt
• lt?php
• echo "PHP displays this message."
• ?gt
• lt/htmlgt

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Connecting to a databaseconnect.php

• lthtmlgt
• lt?php
• // Connection data
• db_name "sample"
• db_username "rwatson"
• db_passwd "secret"
• connect odbc_pconnect(db_name,db_username,d
  b_passwd)
• ?gt
• lt/htmlgt

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Executing SQLexecsql.php

• lthtmlgt
• lt?php
• // Connection data
• db_name "sample"
• db_username "rwatson"
• db_passwd "secret"
• connect odbc_pconnect(db_name,db_username,d
  b_passwd)
• sql "select from shr"
• echo sql
• resultodbc_exec(connect,sql)
• odbc_result_all(result)
• ?gt
• lt/htmlgt

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SQL command entry formsqlcmd.html

• lthtmlgt
• lttitlegtSQL interfacelt/titlegt
• ltbody bgcolor"white"gt
• ltform method"post" action"execsqlcmd.php"gt
• Enter SQL queryltbrgt
• lttextarea name"sqlcmd" rows"5
• cols"60"gtlt/textareagtltbrgt
• ltinput type"Submit"gt
• lt/formgt
• lt/bodygt
• lt/htmlgt

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SQL command entry form
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SQL executionexecsqlcmd.php

• lthtmlgt
• ltbody bgcolor"white"gt
• lt?php
• // Connection data
• db_name "sample"
• db_username "rwatson"
• db_passwd "secret"
• connect odbc_pconnect(db_name,db_username,d
  b_passwd)
• querystripslashes(sqlcmd)
• echo "Query " . htmlspecialchars(query) .
  "ltbrgt\n"
• resultodbc_exec(connect,query)
• odbc_result_all(result)
• ?gt
• ltform action"sqlcmd.html"gt
• ltinput type"submit" value"New query"gt
• lt/formgt
• lt/bodygt
• lt/htmlgt

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Error detectionexecsqlerr.php

• lthtmlgt
• lt?php
• // Connection data
• db_name "sample"
• db_username "rwatson"
• db_passwd "secret"
• connect odbc_pconnect(db_name,db_username,d
  b_passwd)
• sql "select from shr"
• echo sql
• resultodbc_exec(connect,sql)
• if(result 0) echo "SQL command error"
• odbc_result_all(result)
• ?gt
• lt/htmlgt

26
Development with Java

• Java is a platform-independent development
  language
• Java options

27
JDBC

• Java database connection
• Enables development of applications that are OS
  and DBMS independent

28
Processing a SQL query
29
Conclusion

• The Web is giving many applications a new face
• It is relatively easy to create a Web interface
  to a database
• There are many choices
• Open standards are preferable for long-term
  investments
• e.g., PHP or Java