database part 3 – Flashcards
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The entity realtaionship mode is dependent on the database type
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false
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The Crow's Foot model is less implementation-oriented than the Chen model.
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false
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An "entity" in the ER model corresponds to a table.
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true
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In the entity relationship model, a table row corresponds to an entity instance
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true
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In the Chen and Crow's Foot models, an entity is represented with a rectangle containing the entity's name.
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true
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In the original Chen model, each attribute is represented using an oval with the attribute name connected to the entity with a line.
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true
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Software vendors have adopted the Chen representation because of its compact representation.
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false
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A composite identifier is a primary key composed of more than one attribute.
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true
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9. The Crow's Foot notation easily identifies multivalued attributes.
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false
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10. Composite attributes make it easier to facilitate detailed queries.
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false
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11. Relationships between entities always operate in one direction.
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false
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12. Connectivities and cardinalities are established by concise statements known as business rules.
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true
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13. In Chen notation, there is no way to represent cardinality.
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false
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14. In implementation terms, an entity is existence-dependent if it has a mandatory primary key.
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false
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15. A weak relationship exists if the primary key of the related entity contains at least one primary key component of the parent entity.
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false
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16. In a 1:M relationship, to avoid the possibility of referential integrity errors, the data of the "1" side must be loaded first.
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true
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17. Unary relationships are common in manufacturing industries.
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true
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18. Referential integrity and participation are both bidirectional, meaning that they must be addressed in both directions along a relationship.
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false
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19. A weak entity has a primary key that is partially or totally derived from the parent entity in the relationship.
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true
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20. The existence of a mandatory relationship indicates that the minimum cardinality is 0 or 1 for the mandatory entity.
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false
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21. To implement a small database, a database designer must know the "1" and the "M" sides of each relationship and whether the relationships are mandatory or optional.
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true
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22. The process of database design is a sequential process.
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false
