Snowflake Schema
The snowflake schema extends the star schema: dimension tables are further normalized into multiple tables, reducing redundancy but adding joins.
Purpose
To understand the trade-off between star and snowflake schemas and choose the right warehouse schema.
Mechanism
Dimension tables are normalized and split (e.g., a region dimension split into country-province-city). This reduces storage redundancy but queries need more joins. Star queries are simpler and faster; snowflake saves space. Star is more common in practice.
Use cases
- Data warehouse design
- Dimensional modeling
- Schema selection