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BACS 485

BACS 485. Normalization. Data Anomalies. WORKER (WORKER-ID, NAME, SKILL-TYPE, SUPV-ID, BLD-ID). Normalization Process. 0NF. ORDERS ( ORDER-NUM , ORDER-DATE, {PART-NUM, PART-DESC, QTY-ORD, PRICE}). 1NF. ORDERS ( ORDER-NUM , ORDER-DATE, PART-NUM , PART-DESC, QTY-ORD, PRICE). 1NF.

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BACS 485

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  1. BACS 485 Normalization

  2. Data Anomalies WORKER (WORKER-ID, NAME, SKILL-TYPE, SUPV-ID, BLD-ID)

  3. Normalization Process

  4. 0NF ORDERS (ORDER-NUM, ORDER-DATE, {PART-NUM, PART-DESC, QTY-ORD, PRICE})

  5. 1NF ORDERS (ORDER-NUM, ORDER-DATE, PART-NUM, PART-DESC, QTY-ORD, PRICE)

  6. 1NF ORDERS (ORDER-NUM, ORDER-DATE, PART-NUM, PART-DESC, QTY-ORD, PRICE) ORDER-NUM, PART-NUM ---> QTY-ORD ORDER-NUM ---> ORDER-DATE PART-NUM ---> PART-DESC, PRICE

  7. 2NF ORDERS (ORDER-NUM, ORDER-DATE) PART (PART-NUM, PART-DESC, PRICE) ORDER-LINE (ORDER-NUM, PART-NUM, QTY-ORD) Part Orders Order_Line

  8. 3NF Problems CUSTOMER (CUST-NUM, CUST-NAME, CUST-ADDR, SALES-NUM, SALES‑NAME) Customer CUST-NUM ---> CUST-NAME, CUST-ADDR, SALES-NUM, SALES-NAME SALES-NUM ---> SALES-NAME

  9. 3NF Problems CUST-NUM ---> CUST-NAME, CUST-ADDR, SALES-NUM, SALES-NAME SALES-NUM ---> SALES-NAME

  10. 3NF CUSTOMER (CUST-NUM, CUST-NAME, CUST-ADDR, SALES-NUM) SALES-REP (SALES-NUM, SALES-NAME)

  11. BC/NF Problem FACULTY (NAME, DEPT, OFFICE, RANK, DATE-HIRED) OFFICE ---> DEPT NAME, DEPT ---> OFFICE, RANK, DATE-HIRED NAME, OFFICE ---> DEPT, RANK, DATE-HIRED

  12. BC/NF Problem OFFICE ---> DEPT NAME, DEPT ---> OFFICE, RANK, DATE-HIRED NAME, OFFICE ---> DEPT, RANK, DATE-HIRED

  13. BC/NF Solution FAC-LOC (OFFICE, DEPT) FACULTY (NAME, OFFICE, RANK, DATE-HIRED) • The NAME,OFFICE candidate key was chosen as the primary key because the NAME,DEPT candidate key would not be in BCNF. In fact, it would not even be in 2NF since there would be a partial dependency between OFFICE and DEPT.

  14. 0NF Relation FACULTY (FAC-ID, {STU-ID}, {COMMITTEE-CODE})

  15. Normalized? FACULTY (FAC-ID, STU-ID, COMMITTEE-CODE) FAC-NAME --->> STU-ID FAC-NAME --->> COMMITTEE-CODE

  16. 5NF FAC-STU (FAC-ID, STU-ID) FAC-COMM (FAC-ID, COMMITTEE-CODE)

  17. Normalization “Rules” • 0NF to 1NF – Remove repeating groups • 1NF to 2NF – Remove partial functional dependencies • 2NF to 3NF – Remove transitive dependencies • 3NF to BC/NF – Every determinate is a candidate key • BC/NF to 4NF – Remove multi-valued dependencies • 4NF to 5NF – Remove join dependencies • DK/NF – Every constraint is a consequence of domain and key constraints

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