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Chapter 29
Web Technology and DBMSs
Transparencies
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Chapter 29 - Objectives
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Basics of Internet, Web, HTTP, HTML, URLs.
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Advantages and disadvantages of Web as a
database platform.
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Approaches for integrating databases into Web:
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Scripting Languages
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Common Gateway Interface (CGI)
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HTTP Cookies
© Pearson Education Limited 1995, 2005
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Chapter 29 - Objectives
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Extending the Web Server
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Java, J2EE, JDBC, SQLJ, CMP, JDO, Servlets,
and JSP
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Microsoft Web Platform: .NET, ASP, and ADO
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Oracle Internet Platform.
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Introduction
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Web most popular and powerful networked
information system to date.
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As architecture of Web was designed to be
platform-independent, can significantly lower
deployment and training costs.
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Organizations using Web as strategic platform for
innovative business solutions, in effect becoming
Web-centric.
© Pearson Education Limited 1995, 2005
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Introduction
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Many Web sites today are file-based where each
Web document is stored in separate file.
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For large sites, this can lead to significant
management problems.
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Also many Web sites now contain more dynamic
information, such as product and pricing data.
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Maintaining such data in both a database and in
separate HTML files is problematic.

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Accessing database directly from Web would be a
better approach.
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Internet
Worldwide collection of interconnected networks.
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Began in late ‘60s in ARPANET, a US DOD
project, investigating how to build networks that
could withstand partial outages.
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Starting with a few nodes, Internet estimated to
have over 945 million users by end of 2004.
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2 billion users projected by 2010.
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About 3.5 billion documents on Internet (550
billion if intranets/extranets included).
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Intranet and Extranet
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Intranet - Web site or group of sites belonging to an
organization, accessible only by members of that
organization.
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Extranet - An intranet that is partially accessible to
authorized outsiders.
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Whereas intranet resides behind firewall and is
accessible only to people who are members of same
organization, extranet provides various levels of
accessibility to outsiders.
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eCommerce and eBusiness
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eCommerce - Customers can place and pay for orders
via the business’s Web site.
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eBusiness - Complete integration of Internet technology
into economic infrastructure of the business.
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Business-to-business transactions may reach $2.1
trillion in Europe and $7 trillion in US by 2006.
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eCommerce may account for $12.8 trillion in worldwide
corporate revenue by 2006 and could represent 18% of
sales in the global economy.
© Pearson Education Limited 1995, 2005
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The Web
Hypermedia-based system that provides a simple
‘point and click’ means of browsing information on
the Internet using hyperlinks.
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Information presented on Web pages, which can
contain text, graphics, pictures, sound, and video.
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Can also contain hyperlinks to other Web pages,
which allow users to navigate in a non-sequential
way through information.
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Web documents written using HTML.
© Pearson Education Limited 1995, 2005
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The Web
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Web consists of network of computers that can act
in two roles:
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as servers, providing information;
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as clients (browsers), requesting information.
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Protocol that governs exchange of information
between Web server and browser is HTTP and
locations within documents identified as a URL.
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Much of Web’s success is due to its simplicity and
platform-independence.
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Basic Components of Web Environment
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HyperText Transfer Protocol (HTTP)
Protocol used to transfer Web pages through
Internet.

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Based on request-response paradigm:
Connection - Client establishes connection with Web server.
Request - Client sends request to Web server.
Response - Web server sends response (HTML document)
to client.
Close - Connection closed by Web server.
© Pearson Education Limited 1995, 2005
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HyperText Transfer Protocol (HTTP)
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HTTP/1.0 is stateless protocol - each connection is
closed once server provides response.
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This makes it difficult to support concept of a
session that is essential to basic DBMS
transactions.
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HyperText Markup Language (HTML)
Document formatting language used to design most
Web pages.
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A simple, yet powerful, platform-independent
document language.
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HTML is application of Standardized Generalized
Markup Language (SGML), a system for defining
structured document types and markup languages to
represent instances of those document types.

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HyperText Markup Language (HTML)
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Uniform Resource Locators (URLs)
String of alphanumeric characters that represents
location or address of a resource on Internet and
how that resource should be accessed.
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Defines uniquely where documents (resources) can
be found.
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Uniform Resource Identifiers (URIs) - generic set
of all Internet resource names/addresses.
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Uniform Resource Names (URNs) - persistent,
location-independent name. Relies on name lookup
services.
© Pearson Education Limited 1995, 2005
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Uniform Resource Locators (URLs)
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URL consists of three basic parts:
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protocol used for the connection,
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host name,
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path name on host where resource stored.

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Can optionally specify:
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port through which connection to host should be
made,
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query string.
/>© Pearson Education Limited 1995, 2005
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Static and Dynamic Web Pages
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HTML document stored in file is static Web page.
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Content of dynamic Web page is generated each
time it is accessed.
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Thus, dynamic Web page can:
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respond to user input from browser;
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be customized by and for each user.
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Requires hypertext to be generated by servers.
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Need scripts that perform conversions from
different data formats into HTML ‘on-the-fly’.
© Pearson Education Limited 1995, 2005
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Web Services
Collection of functions packaged as single entity and

published to network for use by other programs.
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Web services are important paradigm in building
applications and business processes for the
integration of heterogeneous applications.
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Based on open standards and focus on communication
and collaboration among people and applications.
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Unlike other Web-based applications, Web services
have no user interface and are not targeted for
browsers. Instead, consist of reusable software
components designed to be consumed by other
applications.
© Pearson Education Limited 1995, 2005
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Web Services – Technologies & Standards
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eXtensible Markup Language (XML).
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SOAP (Simple Object Access Protocol) protocol,
based on XML, used for communication over
Internet.
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WSDL (Web Services Description Language)
protocol, again based on XML, used to describe
the Web service.
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UDDI (Universal Discovery, Description and
Integration) protocol used to register the Web

service for prospective users.
© Pearson Education Limited 1995, 2005
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Web Services
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Common example is stock quote facility, which
receives a request for current price of a specified
stock and responds with requested price.
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Second example is Microsoft MapPoint Web
service that allows high quality maps, driving
directions, and other location information to be
integrated into a user application, business process,
or Web site.
© Pearson Education Limited 1995, 2005
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Requirements for Web-DBMS Integration
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Ability to access valuable corporate data in a
secure manner.
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Data- and vendor-independent connectivity to
allow freedom of choice in DBMS selection.
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Ability to interface to database independent of any
proprietary browser or Web server.
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Connectivity solution that takes advantage of all
the features of an organization’s DBMS.
© Pearson Education Limited 1995, 2005

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Requirements for Web-DBMS Integration
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Open architecture to allow interoperability with a
variety of systems and technologies. For example:
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different Web servers;
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Microsoft's (Distributed) Common Object Model
(DCOM/COM);
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CORBA/IIOP (Internet Inter-ORB protocol);
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Java/Remote Method Invocation (RMI);
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XML;
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Web services (SOAP, WSDL, UDDI).
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Cost-effective solution that allows for scalability,
growth, and changes in strategic directions, and helps
reduce applications development costs.
© Pearson Education Limited 1995, 2005
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Requirements for Web-DBMS Integration
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Support for transactions that span multiple HTTP
requests.
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Support for session- and application-based

authentication.
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Acceptable performance.
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Minimal administration overhead.
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Set of high-level productivity tools to allow
applications to be developed, maintained, and
deployed with relative ease and speed.
© Pearson Education Limited 1995, 2005
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Advantages of Web-DBMS Approach
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DBMS advantages
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Simplicity
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Platform independence
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Graphical User Interface
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Standardization
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Cross-platform support
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Transparent network access
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Scalable deployment
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Innovation

© Pearson Education Limited 1995, 2005