What are two commonly used dimensional modeling schemas?

The two commonly used dimensional modeling schemas in data warehousing are the star schema and the snowflake schema.

The star schema is characterized by a central fact table that is directly connected to multiple dimension tables. This design is straightforward and allows for easy querying, making it highly efficient for reporting and analysis. The structure resembles a star, with the fact table at the center and the dimensions surrounding it, which is where it derives its name.

On the other hand, the snowflake schema is a more normalized version of the star schema. In this setup, dimension tables are further broken down into sub-dimensions, creating a more complex structure that resembles a snowflake. While this schema can reduce data redundancy and improve data integrity, it can also lead to more complex queries and potentially slower performance when compared to the star schema.

Understanding these schemas is crucial for designing efficient data models tailored to the specific needs of reporting and analysis in Oracle Analytics.