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Week 6 Textbook assignments

Week 6 Textbook assignments - 8 Data redundancies might...

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8. Data redundancies might lead to the following three data anomalies: Update anomalies – Modifying one attribute for one entity would require changes in each table with that corresponding entity. Insertion anomalies – When a fictitious entity must be created to complete the data entry of another entity. Deletion anomalies – When a fictitious entity must be created just to save the data in a table that is link to the fictitious. 10. A surrogate key is an artificial PK (Primary key) used by the designer with the purpose of simplifying the assignment of primary keys to tables. Surrogate keys are usually numeric, they
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