QUESTIONS
- What in data modeling? Why is it important? 2. What is the Entity-Relationship model? 3. What is the relationship? 4. What are the differences among aunary relationship, ' a binary relationship, and a ternary relationship? 5. Explain and compare the cardinality of a relationship and the modality of a relationship. 6. Explain the difference between a one-to-one, a one-. to-many, and a many-to-many binary relationship. 7. What is intersection data in a many-to-many binary relationship? What does the intersection data describe? 8. Can a many-to-many binary relationship have no intersection data? Explain. 9. Can intersection data be placed in the entity box of one of the two entities in the many-to-many relationship? Explain.
- What is an associative entity? How does intersection data relate to an associative entity? 11. Describe the three cases of unique identifiers for associative entities. 12. Describe the concept of the unary relationship. 13. Explain how a unary relationship can be described as one-to-one, one-to-many, and many-to-many if. only one entity type is involved in the relationship. 14r Describe the ternary relationship concept 15. Can a ternary relationship have intersection data? 16. What is a dependent entity? (See the description in the General Hardware example.)
Sample Solution