Differences between the Star and Snow flake schemas in Dimensional Modeling


Star Schema:

1.   In a start schema, the fact table will be at the center and is connected to the dimension tables.

2.   The tables are completely in de normalized structure.

3.   SQL queries performance is good as there are less number of joins involved.

4.   Data redundancy is high and occupies more disk space.

Snow Flake Schema:

1.   Snow flake schema is an extension of star schema where the dimension tables are further connected to one or more dimensions.

2.   The tables are partially de normalized in structure.

3.   The performance of SQL queries are a bit less when compared to star schema as more number of joins are involved.

4.   Data redundancy is low and occupies less disk space when compared to star schema.

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