Data Mining Interview Questions and Answers

 

What are cubes?

"An OLAP cube (for online analytical processing) is a data structure that allows
fast analysis of data. It can also be defined as the capability of manipulating
and analyzing data from multiple perspectives. The arrangement of data into cubes
overcomes some limitations of relational databases.




OLAP cubes can be thought of as extensions to the two-dimensional array of a spreadsheet.
For example a company might wish to analyze some financial data by product, by time-period,
by city, by type of revenue and cost, and by comparing actual data with a budget.
These additional methods of analyzing the data are known as dimensions. Because
there can be more than three dimensions in an OLAP system the term hypercube is
sometimes used.




FunctionalityThe OLAP cube consists of numeric facts called measures which are categorized
by dimensions. The cube metadata (structure) may be created from a star schema or
snowflake schema of tables in a relational database. Measures are derived from the
records in the fact table and dimensions are derived from the dimension tables."

Posted by:Richards