TRENDS IN DATABASE TECHNOLOGY - Database Design and Development: An Essential Guide for IT Professionals - page 653

How many steps are there? Many steps, but a single analysis session. Many steps,
but a single train of thought. Each step in this train of thought constitutes a query.
The analyst formulates each query, executes the query, waits for the result set to
appear on the screen, and studies the result set. Each query is interactive because
the result set from one query forms the basis for the next query. In this manner of
querying, the user cannot maintain the train of thought unless the momentum is
preserved. Fast access is absolutely essential for an effective analytical processing
environment.
Did you notice that none of the queries in the above analysis session
included any serious calculations? This is not typical. In a real-world analysis
session, many of the queries require calculations, sometimes, complex calculations.
What is the implication here? An effective analytical processing environment
must not only be fast and flexible, it must also support complex and powerful
calculations.
What follows is a list of typical calculations that get included in the query
requests:
• Roll-ups to provide summaries and aggregations along the hierarchies of the
dimensions
• Drill-downs from the top level to the lowest along the hierarchies of the dimen-
sions, in combinations among the dimensions
• Simple calculations such as computation of margins (sales minus costs)
• Share calculations to compute the percentage of parts to the whole
• Algebraic equations involving key performance indicators
• Moving averages and growth percentages
• Trend analysis using statistical methods
Features and Functions OLAP provides users with the ability to perform
multidimensional analysis with complex calculations.
Here is a summary list of features and functions of OLAP:
• Enables analysts, executives, and managers to gain useful insights from the
presentation of data.
• Can reorganize metrics along several dimensions and allow data to be viewed
from different perspectives.
• Supports multidimensional analysis.
• Is able to drill down or roll up within each dimension.
• Is capable of applying mathematical formulas and calculations to measures.
• Provides fast response, facilitating speed-of-thought analysis.
• Complements the use of other information delivery techniques such as data
mining.
• Improves the comprehension of result sets through visual presentations using
graphs and charts.
• Can be implemented on the Web.
• Designed for highly interactive analysis.