Answered by sudhakar on 2005-05-09 18:32:18: star schema uses denormalized dimension tables,but in case of snowflake schema it uses normalized dimensions to avoid redundancy...
No best answer available. Please pick the good answer available or submit your answer.
March 13, 2005 12:51:00
RE: Differences between star and snowflake schemas
The star schema is created when all the dimension tables directly link to the fact table. Since the graphical representation resembles a star it is called a star schema. It must be noted that the foreign keys in the fact table link to the primary key of the dimension table. This sample provides the star schema for a sales_ fact for the year 1998. The dimensions created are Store Customer Product_class and time_by_day. The Product table links to the product_class table through the primary key and indirectly to the fact table. The fact table contains foreign keys that link to the dimension tables.
RE: Differences between star and snowflake schemas
The snowflake schema is a schema in which the fact table is indirectly linked to a number of dimension tables. The dimension tables are normalized to remove redundant data and partitioned into a number of dimension tables for ease of maintenance. An example of the snowflake schema is the splitting of the Product dimension into the product_category dimension and product_manufacturer dimension..
RE: Differences between star and snowflake schemas
Read more on this here .... http://www.exforsys.com/content/view/1301/332/This tutorial covers Designing the Dimensional Model Dimensional Model schemas like Star Schema Snowflake Schema Optimizing star schema and Design of the Relational Database OLAP Cubes and Data mining tools Security considerations metadata and backup and recovery plans
RE: Differences between star and snowflake schemas
Star Schema snowflake schema ----------- ---------------- Star schema is normalised Denormalised. Easy to use and understand End users will gt confused. Want little efforts for maintainance Easy to maintain Fast execution of queries More time for exec bcas of more joins
