Sparsity and Density, Sparse and Dense

Sparsity and Density, Sparse and Dense - The degree to which the cells of a cube are filled with data.

One of the primary challenges of storing multidimensional data is the degree of sparsity that is often encountered. When many dimensions are considered with a fine grain of detail, most of the cells will be empty.

It is not uncommon for large cubes to have data in fewer than one in a million cells. Expressed numerically, that cube would have a density of less than .0001%.

[Category=Data Warehousing ]

Source: SDG Computing Inc., 12 May 2010 11:22:00, SDG Computing, now offline

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sparsity and density - Sparsity and density are terms used to describe the percentage of cells in a database table that are not populated and populated, respectively. The sum of the sparsity and density should equal 100%.

A table that is 10% dense has 10% of its cells populated with non-zero values. It is therefore 90% sparse – meaning that 90% of its cells are either not filled with data or are zeros.

Because a processor adds up the zeros, sparcity can negatively impact processing time. In a multidimensional database sparsity can be avoided by linking cubes. Instead of creating a sparse cube for data that is not fully available, a separate but linked cube will ensure the data in the cubes remains consistent without slowing down processing.

Related glossary terms: columnar database, Not Only SQL (NoSQL), Amazon Dynamo Database (DDB), On-Line Analytical Processing (OLAP), in-memory database, Google BigTable, denormalization, virtual cube, Cassandra (Apache Cassandra), data classification

[Category=Data Management ]

Source: WhatIs.com, 09 September 2013 09:12:59, http://whatis.techtarget.com/glossary/Data-and-Data-Management