Data Warehousing 281
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DATA WAREHOUSING
AND THE WEB
Objectives
• Understand what Web-enabling the data
warehouse means and examine the reasons
for doing so
• Appreciate the implications of the
convergence of Web technologies and those
of the data warehouse
• Probe into all the facets of Web-based
information delivery
• Study how OLAP and the Web connect and
learn the different approaches to connecting
them
• Examine the steps for building a Webenabled data warehouse
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DATA WAREHOUSING AND THE WEB
• The Internet with the Worldwide Web is the most dominant
phenomenon in computing and communication that
started
• in the 1990s
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WEB-ENABLED DATA WAREHOUSE
• A Web-enabled data warehouse uses the Web for information
delivery and collaboration among users.
• As months go by, more and more data warehouses are being
connected to the Web.
• Why the Web?
Internet.
Intranet.
Extranet.
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Data warehouse and the Web.
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Convergence of Technologies
• There is no getting away from the fact that Web
technology and data warehousing have converged, and
the bond is only getting stronger.
• Fast response, although some Web pages are comparatively
slower
• Extremely easy and intuitive to use
• Up 24 hours a day, 7 days a week
• More up-to-date content
• Graphical, dynamic, and flexible user interfaces
• Almost personalized display
• Expectation to connect to anywhere and drill across
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Adapting the Data Warehouse for the Web
• Requisites for adapting the data warehouse to the web.
• Information “Push” Technique. The data warehouse was designed and implemented
“pull” technique. The information delivery system pulls information from the data
warehouse based on requests, and then provides it to the users. The Web offers
another technique. The Web can “push” information to users without their asking for it
every time. Your data warehouse must be able to adopt the “push” technique.
• Ease of Usage. With the availability of click stream data, you can very quickly check
of the user at the site. Among other things, click stream data reveals how easy or
difficult it is for the users to browse the pages. Ease of use appears at the top of the
list of requirements.
• Speedy Response. Some data warehouses allow jobs to run long to produce the
In the Web model, speed is expected and cannot be negotiated or compromised.
• No Downtime. The Web model is designed so that the system is available all the time.
• Similarly, the Web-enabled data warehouse has no downtime.
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The Web as a Data Source
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WEB-BASED INFORMATION DELIVERY
• Better information delivery remains the most compelling
reason for adapting the data warehouse for the Web.
• The Web brings a new outlook on information delivery and
revolutionizes the process.
• How does the Web escalate the usage of the data
warehouse?
• What are the benefits and what are the challenges?
• How do you deal with the dramatic change in information
delivery brought about by the Web?
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Information Delivery Guidelines.
• Performance. Industry experts agree on a less than 10-second response time
for a page to deliver the first screen of useful contents.
• User Options. Users are conditioned to expect to see a number of standard
options when they arrive at a Web page. These include navigation selections.
selections.
• User Experience. Every Web designer’s fondest goal is to make each page a
pleasing experience for the user. Users are eager to visit and stay on a page
a page that is nicely formatted.
• User Support. In a lengthy process, a user must have the reassurance that
nothing will be lost in the middle of the process
• Self-service Access. As the Web opens up the data warehouse to more users,
both inside and outside the enterprise, tools must provide autonomous
autonomous access to information.
• Users must be able to navigate and drill out to information sources
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OLAP and the Web
• Web-enabled data warehouses can open their doors to a
large group of users both within and outside the
enterprise, and OLAP services be extended to more than
a select group of analysts.
• Dr. Ralph Kimball popularized a new term, “data
Webhouse,” which included the notion of a Web-enabled
data warehouse.
• He declared that the data warehouse is taking central
stage in the Web revolution
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Web-OLAP Approaches
• Browser Plug-ins. In the first approach, you use plug-ins or browser
extensions.
• Pre-created HTML Documents. In the next approach, you provide precreated HTML documents along with the navigation tools to find these.
find these. The documents are result sets of analytical operations.
operations.
• This approach takes advantage of Web technology and thin-client economy, but
economy, but users are confined to using predefined reports.
• OLAP in the Server. The best approach is to use the server to do all
online analytical processing and present the results on a true thin-client
thin-client information interface.
• This approach realizes the economic benefits of the Web and thin-client
client architecture.
• At the same time, it provides an integrated server environment irrespective of
irrespective of the client machines. Maintenance is minimized because
applications and logic are centralized on the server.
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BUILDING A
WEBENABLED
DATA
WAREHOUSE
• Nature of the Data Webhouse
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Implementation Considerations
Web Processing Model
• Notice that the
architecture is more
complex that a two-tier
tier or three-tier
client/server
architecture.
• You need additional tiers
tiers to accommodate
accommodate the
requirements of Web
computing.
• At a minimum, you need
need to have a Web
server between the
browser clients and the
the database.
• Also, note the firewall to
to protect your
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Web processing
model.
• The model illustrates how HTML pages are translated into SQL
queries passed on to the DBMS using CGI scripts.
• This model shows the components for information delivery
through HTML pages.
• The model may be generalized to illustrate other technologies.
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Questions
1.
2.
3.
4.
Describe briefly two major features of the Web-enabled data warehouse.
How do the Internet, intranet, and extranet apply to the data warehouse?
What are the expectations of users from a Web-enabled data warehouse?
How can you use the Web as a data source for your data warehouse? What
types of information can you get from the Web?
5. Name any four standard options on a Web page delivering information from
the data warehouse.
6. What are the four common technologies to build Web-enabled user interfaces
for your data warehouse?
7. Why is data security a major concern for a Web-enabled data warehouse?
8. List any four features of the data Webhouse.
9. Name any two approaches for an OLAP system to function in a Web-enabled
data warehouse.
10. What is a data warehouse bus architecture? How does it fit in a Web-enabled
data warehouse?
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Discussion Questions
1. Web-based information in a data warehouse results in
“supergrowth.” Discuss this phenomenal growth and describe how
you will provide for supergrowth.
2. Your project team has been directed to provide all report
generation and delivery over the Internet. Create a plan for
adopting the Web technology for all reporting from your data
warehouse. Discuss all the implications.
3. The Web-enabled data warehouse has no centre. It is a
distributed environment. Analyse the implications of these
statements. From this perspective, what are the considerations for
maintaining the dimension and fact tables?
4. As the Web specialist on the project team, prepare a document
highlighting the major considerations for Web-enabling your data
warehouse. Just list the considerations, not the implementation
techniques.
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