Discover the star schema, a denormalized database structure composed of a fact table and denormalized dimension tables, optimized for efficient querying and data analysis.
Table of Contents
Question
A database consists of one fact table that is composed of multiple dimensions. Each dimension is represented by a denormalized table. This structure is an example of a:
A. non-relational schema.
B. galaxy schema.
C. snowflake schema.
D. star schema.
Answer
D. star schema.
Explanation
A star schema is a denormalized database structure composed of a central fact table and multiple denormalized dimension tables. The fact table contains the primary keys of the dimension tables and the measures or metrics being analyzed. Each dimension table represents a specific aspect of the data, such as time, location, or product, and contains descriptive attributes related to that dimension.
In a star schema, the dimension tables are denormalized, meaning they store redundant information to avoid the need for complex joins during querying. This denormalization improves query performance by reducing the number of tables that need to be joined and allowing for faster data retrieval.
The star schema is optimized for data warehousing and online analytical processing (OLAP) scenarios, where efficient querying and data analysis are the primary goals. It provides a simple and intuitive structure that enables users to easily navigate and understand the relationships between the fact table and the dimension tables.
Key characteristics of a star schema include:
- Single fact table: The central table contains the measures and foreign keys to the dimension tables.
- Denormalized dimension tables: Each dimension is represented by a single, denormalized table.
- Simplified joins: Querying involves joining the fact table with the relevant dimension tables, resulting in faster query performance.
- Redundant data: Dimension tables store redundant information to avoid complex joins and improve query speed.
The other options mentioned are not accurate descriptions of the given scenario:
- A non-relational schema refers to a database structure that does not follow the traditional relational model, such as NoSQL databases.
- A galaxy schema is not a commonly used term in database design.
- A snowflake schema is a variation of the star schema where dimension tables are normalized, resulting in a more complex structure with multiple levels of relationships.
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