Both of these are multidimensional models deployed for a data warehouse. There is a primary difference between Star Schema and Snowflake Schema. The Star Schema contains the dimension tables and fact tables- but the Snowflake schema contains sub-dimension tables as well, along with both of these. In this article, we will discuss more ways in which both of them vary. Read ahead to know more.
What is a Star Schema?
It is a multidimensional model type that one can use in the case of a data warehouse. A typical Star Schema contains both- the dimensional tables and the fact tables. It also makes use of a fewer number of foreign-key joins. In simpler words, this type of schema leads to the formation of a star with dimension tables and fact tables.
What is a Snowflake Schema?
It is also a multidimensional model type that one can use in the case of a data warehouse. A typical Snowflake Schema contains all three- dimension tables, fact tables, and sub-dimension tables. In simpler words, this type of schema leads to the formation of a snowflake with dimension tables, fact tables, and also sub-dimension tables.
Difference Between Star Schema and Snowflake Schema
|Parameters||Star Schema||Snowflake Schema|
|Definition and Meaning||A star schema contains both dimension tables and fact tables in it.||A snowflake schema contains all three- dimension tables, fact tables, and sub-dimension tables.|
|Type of Model||It is a top-down model type.||It is a bottom-up model type.|
|Space Occupied||It makes use of more allotted space.||It makes use of less allotted space.|
|Time Taken for Queries||With the Star Schema, the process of execution of queries takes less time.||With the Snowflake Schema, the process of execution of queries takes more time.|
|Use of Normalization||The Star Schema does not make use of normalization.||The Snowflake Schema makes use of both Denormalization as well as Normalization.|
|Complexity of Design||The design of a Star Schema is very simple.||The designing of a Snowflake Schema is very complex.|
|Query Complexity||It is very low in the case of a Star Schema.||It is comparatively much higher in the case of a Snowflake Schema.|
|Complexity of Understanding||It is very easy to understand a Star Schema.||It is comparatively more difficult to understand a Snowflake Schema.|
|Total Number of Foreign Keys||The total number of foreign keys is less in the case of a Star Schema.||The total number of foreign keys is more in the case of a Snowflake Schema.|
|Data Redundancy||Data redundancy is comparatively higher in Star Schema.||Data redundancy is comparatively lower in Snowflake Schema.|
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