Web Technology and DBMSs

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Web Technology and DBMSs

• Martin Slouka
• Martin.Slouka_at_tut.fi
• Lucie Hrbková
• Lucie.Hrbkova_at_uta.fi

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Contents

• HTTP
• HTML
• Two-tier vs. n-tier
• Advantages Disadvantages of Webtechnology
• Cookies Sessions
• CGI API
• Scripting Languages

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HTTP (HyperText Transfer Protocol)

• Standard
• Generic
• Stateless
• Negotiation of data representation

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HTML (HyperText Markup Language)

• Standard
• Non-proprietary format
• Uses tags to structure text
• Can include images
• Extensions
• Javascript Jscript
• CSS (Cascading Style Sheets)

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Two - Tier
Tier 1
Tier 2
Database server
Application
Database
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n - Tier
Tier 3
Tier 4
Tier 2 Server
Tier 1 Client
Database server
Application server
Database
Web server
Workstation
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Advantages of Webtechnology

• Simplicity
• Platform Independence
• Graphical User Interface
• Standardization
• Transparent Network Access

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Disadvantages of Webtechnology

• Reliability
• Security
• Need of scalability
• Limited functionality of HTML
• Statelessness
• Bandwidth
• Performance

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Cookies

• Stored in browser
• Sent with each request
• Not reliable

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Sessions

• Temporary Information
• Stored on server side
• Client - Session assignment

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CGI (Common Gateway Interface)

• Simple
• Language independent
• Web server independent
• New process

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API (Aplication Programming Interface)

• NO new process
• More facilities
• Web server dependent
• Can crash web server

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Scripting Languages

• JavaScript
• JScript
• VBScript
• Perl
• PHP
• Java
• other proprietary languages

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JavaScript JScript

• Object Oriented
• Interpreted
• Server side / Client side

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VBScript

• Microsoft proprietary
• Interpreted
• Extended and secured Visual Basic
• Server side
• Client side (IE only)

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Perl (Practical Extraction and Report Language)

• Combines functions of C, sed, awk, sh
• Interpreted
• Text processing capabilities
• Server side

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PHP

• HTML-embeded
• Interpreted
• Extensible with modules
• Server side

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Java

• Sun Microsystems proprietary
• Object oriented
• Networked design
• Architecture independent
• Client side (precompiled applets)
• Server side (precompiled servlets)

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Any questions?
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Thank you!