Question

    Which of the following best describes a fact

    constellation schema in a data warehouse?
    A A schema with a single large central fact table connected to multiple dimension tables Correct Answer Incorrect Answer
    B A schema where each dimension has its own hierarchy in a tree structure Correct Answer Incorrect Answer
    C A schema consisting of multiple fact tables sharing many dimension tables Correct Answer Incorrect Answer
    D A normalized schema that eliminates redundancy in dimension data Correct Answer Incorrect Answer
    E A schema used only for OLTP systems, not OLAP Correct Answer Incorrect Answer

    Solution

    A fact constellation schema, also known as a galaxy schema, is a complex schema used in a data warehouse where: • Multiple fact tables exist (e.g., Sales Fact, Shipment Fact). • These fact tables share dimension tables (like Time, Product, Customer). • It supports complex business processes that cannot be represented by a single fact table. This schema is more advanced than star and snowflake schemas and is suitable for enterprise-level data warehousing. • Option A describes a star schema. • Option B vaguely refers to hierarchy in dimensions (e.g., snowflake). • Option D refers to normalization, relevant for snowflake schema but not fact constellation. • Option E is incorrect because fact constellation is used in OLAP systems.

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