Consider the following tables:

REGION(REG_CODE, REG_DESCRIPTION, REG_LOCATION)

STORE(ST_CODE, ST_NAME, ST_MANAGER, REG_CODE)

For the tables given above, work on the problems below:

1. Identify at least one candidate key. If there are no candidate keys, give an example of an attribute that could be used as a candidate key.

2. For one of the tables, give examples of a superkey and a secondary key.

3. For the given tables, explain how entity integrity and referential integrity could be violated. Give specific examples.

4. Use Visio to create a detailed Crow's Foot ERD. The diagram must include all entities, attributes, and relationships. Primary keys and foreign keys must be clearly identified on the diagram.