Chapter 40

Question 1

What are dimensions in dataware house

Answer 1

A dimension is a structure that categorizes facts and measures in order to enable users to answer business questions. Commonly used dimensions are people, products, place and time.

Question 2

What are famous Web Warehouse Dimensions

Answer 2

Date, Time of day, Part Vendor, Transaction, Status

Question 3

What happen when definition of static page changes

Answer 3

When the definition of a static page changes because the Webmaster alters it, the row in the page dimension either can be overwritten or can be treated as a slowly changing dimension.

Question 4

What is clickstream

Answer 4

clickstream is every page event recorded by each of the company’s Web servers

Question 5

What are dimensions of clickstream

Answer 5

The clickstream contains a number of new dimensions such as page, session, and referrer

Question 6

What are the issues with clickstream data

Answer 6

Clickstream data has many issues. like

• Identifying the Visitor Origin
• Identifying the Session
• Identifying the Visitor
• Proxy Servers.
• Browser Caches

Question 7

How can we identify a session on web as HTTP is stateless

Answer 7

There are several ways to do this
Using Time-contiguous Log Entries
Using Transient Cookies
Using HTTP’s secure sockets layer (SSL)
Using session ID Ping-pong.
Using Persistent Cookies.

Question 8

What are Transient Cookies

Answer 8

session-level cookie into the visitor’s Web browser. Using a transient cookie value as a temporary session ID for both the clickstream and application logging allows a straightforward approach to associating the data from both these sources during post session log processing.

Question 9

what is super session

Answer 9

cer­tain groups of Web sites can agree to store a common ID tag that would let these sites combine their separate notions of a visitor session into a super session.

Question 10

What are proxy servers

Answer 10

Proxy servers are used to cache frequently requested content at a location between its intended source and an end visitor.

Question 11

What are 3 problems caused by proxy servers

Answer 11

1. A proxy may deliver outdated content
2. Proxies may satisfy a content request without properly notifying the originating server that the request has been served by the proxy.
3. If the visitor has come though a proxy, the Web site will not know who made the page request unless a cookie is present.

Question 12

What are 2 types of proxy servers

Answer 12

1. Forward proxy

2. Reverse proxy

Question 13

What are challenges to web dataware house

Answer 13

1. Teaming
2. Beware of slow string functions (slow insertion and data manipulation)
3. Large data so minimum loading