What are the two commonly used dimensional modeling schemas?

The commonly used dimensional modeling schemas are primarily the Star schema and the Snowflake schema. The Star schema is characterized by a central fact table surrounded by dimension tables, which are directly connected to it. This design facilitates simple queries and is optimized for performance in data retrieval, making it highly suitable for data warehouses and analytical applications. It provides an intuitive structure that makes it easier for analysts and users to understand the relationships between data.

On the other hand, the Snowflake schema is a more normalized version of the Star schema. In this case, the dimension tables are broken down into related tables, which reduces data redundancy. However, the added complexity of the Snowflake schema may lead to slower query performance compared to the Star schema.

Given the context of the question, while the Star schema is one of the most recognized designs for dimensional modeling due to its efficiency and ease of use, the Snowflake schema also plays a significant role in data warehousing. Therefore, the essential understanding is that the Star schema is frequently referenced alongside the Snowflake schema when discussing dimensional modeling, making your answer, which identifies the Star schema as a commonly used model, a valid choice within the context of this question.