The star schema and the snowflake schema are ways to organize data marts or entire data warehouses using
relational databases. Both of them use dimension tables to describe data aggregated in a fact table.
Everyone sells something, be it knowledge, a product, or a service. Storing this information, either in an
operational system or in a reporting system, is also a need. So we can expect to find some type of sales
model inside the data warehouse of nearly every company.
Let’s take one more look at the sales model in both the star and snowflake schemas.
This snowflake schema stores exactly the same data as the star schema. The fact table has the same
dimensions as it does in the star schema example. The most important difference is that the dimension tables
in the snowflake schema are normalized. Interestingly, the process of normalizing dimension tables is called
snowflaking.
Once again, visually the snowflake schema reminds us of its namesake, with several layers of dimension
tables creating an irregular snowflake-like shape.
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