Schema suitability: Evaluate the claim. “Star schema is suited to online transaction processing (OLTP) and therefore is generally used in operational systems, operational data stores (ODS), or an enterprise data warehouse (EDW).”
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AIncorrect
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BCorrect
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CCorrect only for micro-batch ODS
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DValid when star has snowflaked dimensions
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EIndeterminate without workload statistics
Answer
Correct Answer: Incorrect
Explanation
Introduction / Context: Star schemas place a central fact table at a defined grain with surrounding dimensions for slicing and dicing. They are optimized for analytics (OLAP)—fast aggregations, drill downs, and ad hoc queries—not for high-volume transactional updates typical of OLTP systems. This statement claims star is suited to OLTP and used in operational stores; we must assess that.
Given Data / Assumptions:
- OLTP emphasizes write performance, strict normalization, and transaction integrity.
- OLAP emphasizes read performance, denormalization, and query simplicity.
- ODS may use more normalized structures to mirror sources for integration and light reporting.
Concept / Approach: Star schemas favor denormalization and surrogate keys to enable fast aggregates and simpler joins, trading off some update anomalies that are irrelevant for read-mostly analytics. OLTP uses normalized 3NF designs to avoid redundancy during frequent inserts/updates. Therefore, stars are generally for EDW or data marts, not for operational systems or ODS cores.
Step-by-Step Solution:
Identify workload: OLTP (many small writes) vs. OLAP (fewer large reads).Map to schema strategy: 3NF for OLTP; star/snowflake for OLAP.Conclude the claim linking star to OLTP is incorrect.Note that EDWs do use stars, but the reason is OLAP suitability, not OLTP suitability.Verification / Alternative check: Benchmark analytical queries on star vs. 3NF: star typically reduces joins and improves aggregation speed; OLTP updates favor 3NF.
Why Other Options Are Wrong:
- “Correct” conflicts with well-established workload design principles.
- “Micro-batch ODS” and “snowflaked dimensions” are tangential and do not convert OLTP into OLAP.
- “Indeterminate” is unnecessary; the design intent is clear.
Common Pitfalls: Forcing star schemas into heavily transactional contexts; misunderstanding ODS vs. EDW roles; mixing grains in a single fact table.
Final Answer: Incorrect