Question

1. To keep track of vendors and products they supply, XYZ Corp. uses the table structure shown below. Assuming that the sample data are representative, draw a dependency diagram in Visio that shows all functional dependencies including both partial and transitive dependencies. (Hint: Look at the sample values to determine the nature of the relationships.)

PART_CODE	PART_DESC	VEND_NAME	VEND_ADDRESS	VEND_TYPE	PRICE
1234	Logic Chip	Fast Chips	Cupertino	Non-profit organization	25.00
1234	Logic Chip	Smart Chips	Phoenix	Non-profit organization	22.00
5678	Memory Chip	Fast Chips	Cupertino	Profit organization	18.00
5678	Memory Chip	Quality Chips	Austin	Profit organization	15.00
5678	Memory Chip	Smart Chips	Phoenix	Profit organization	19.00

2. Using the initial dependency diagram drawn in question 1, remove all partial dependencies, draw the new dependency diagrams in Visio, and identify the normal forms for each table structure you created.

3. Using the table structures you created in question 2, remove all transitive dependencies, and draw the new dependency diagrams in Visio. Also identify the normal forms for each table structure you created.  If necessary, add or modify attributes to create appropriate determinants or to adhere to the naming conventions.

4. Using the results of question 3, draw the fully labeled Crow's Foot ERD in Visio. The diagram must include all entities, attributes, and relationships. Primary keys and foreign keys must be clearly identified on the diagram.

Answer 1

1. PART_CODE-->PART_DESC, PART_DESC-->VEND_TYPE, VEND_NAME-->VEND_ADDRESS

CANDIDATE KEYS: {PRICE}, {PART_CODE, VEND_ADDRESS}, {PART_DESK, VEND_ADDRESS}, {VEND_ADDRESS, VEND_TYPE }.

All attributes are prime based on the attribute values.

There is no such non-prime attributes, indicating partial dependencies.

Transitive dependencies (based on prime attributes): PART_CODE-->PART_DESC, PART_DESC-->VEND_TYPE

2. Since, there is no partial dependencies and transitive dependencies with respect to non-prime attributes. Hence, the relation is in 3 normal form.

For Boyce codd normal form, individual relation will be created based on each functional dependencies and they should have primary key (PK) and foreign key (FK) relationship in all 2 relations (based on PART_CODE-->PART_DESC,

PART_DESC-->VEND_TYPE).

3. Relation1: (PART_CODE (PK), PART_DESC(FK), VEND_TYPE)

Relation2: (PART_DESC (PK), VEND_TYPE)