Decomposition and Normalization Fan Qi

Anomalies in Database Design Insertion Anomaly – Certain facts cannot be inserted Update Anomaly – Update a fact causes changes in multiple places Deletion Anomaly – Delete a fact cause deletion of other facts Faculty IDFaculty NameOfficeHire DateCourse Code 389Dr. GroveCom Feb-1985CS Dr. SapersteinCom Apr-1999CS Dr. SapersteinCom Apr-1999CS Dr. NewsomeCom Oct-2015 No course assigned, cannot insert Update Office Cause Inconsistency Delete CS433 affect entire row

Normalization Organizing columns and tables to minimize data redundancy – So the anomalies are resolved Normal Forms: – 1NF No set values Key must exists (no duplicate rows) – 2NF No non-prime attribute is dependent on part of any keys – 3NF Non-prime attributes are dependent only on the key – BCNF Every attribute is dependent only on the key

Normalization

Decomposition

3NF Decomposition

BCNF Decomposition

Final Notes [1]