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Thursday, November 3, 2011

Snowflake Schema in Data Warehouse


Introduction
The snowflake schema is an extension of the star schema, where each point of the star explodes into more points. In a star schema, each dimension is represented by a single dimensional table, whereas in a snowflake schema, that dimensional table is normalized into multiple lookup tables, each representing a level in the dimensional hierarchy.




Advantages:

  1. The biggest advantage of snowflake schema is improved query performance.
  2. Reduces dimension table size.

Disadvantage:

  1. Additional maintenance efforts needed due to the increase number of lookup or detail tables


1 comment:

Albina N muro said...

Star and snowflake schemas are most commonly found in dimensional data warehouses and data marts where speed of data retrieval is more important. survival warehouse food supplies