Chapter 4 (True/False)

Question 1

1) An ERM is dependent on the database type.

Answer

true

Question 2

2) The word “entity” in the ER model corresponds to a table.

Answer

true

Question 3

3) The Crow’s Foot model is less implementation-oriented than the Chen model.

Answer

true

Question 4

4) The ER diagram represents the conceptual database as viewed by the end user.

Answer

true

Question 5

5) The ER model refers to a specific table row as an entity instance.

Answer

true

Question 6

6) In both the Chen and Crow’s Foot models, an entity is represented with a rectangle containing the entity’s name.

Answer

true

Question 7

7) The ER model refers to a specific table row as an entity occurrence.

Answer

true

Question 8

8) Attributes are types of entities.

Answer

true

Question 9

9) In the original Chen model, each attribute is represented using an oval with the
attribute name connected to the entity with a line.

Answer

true

Question 10

10. Software vendors have adopted the Chen representation because of its compact
representation.

Answer

true

Question 11

11) Attributes have a domain that specifies the data type of the attribute.

Answer

true

Question 12

12) Attributes cannot share a domain.

Answer

true

Question 13

13) In an ER diagram, primary keys are usually bolded.

Answer

true

Question 14

14. Ideally, a primary key is composed of several attributes.

Answer

true

Question 15

15. A composite identifier is a primary key composed of more than one attribute.

Answer

true

Question 16

16. All attributes are either simple or composite.

Answer

true

Question 17

17) All simple attributes are also single-valued.

Answer

true

Question 18

18) In the Chen model, a multivalued attribute is connected to the owning entity
with a double line.

Answer

true

Question 19

19) The DBMS can easily handle multivalued attributes.

Answer

true

Question 20

20) Derived attributes are stored in a special database table.

Answer

true

Question 21

21) A relationship is identified by a name that describes the relationship.

Answer

true

Question 22

22) Cardinality expresses the minimum and maximum number of entity occurrences associated with one occurrence of the related entity.

Answer

true

Question 23

23) In Chen notation, there is no way to represent cardinality.

Answer

true

Question 24

24) Connectivities and cardinalities are established by business rules.

Answer

true

Question 25

25) A weak relationship exists if the primary key of the related entity contains at least one primary key component of the parent entity.

Answer

true

Question 26

26) You should always load data from the 1 side of a 1:M relationship.

Answer

true

Question 27

27) A weak entity has a primary key that is partially or totally derived from the parent entity in the relationship

Answer

true

Question 28

28. The existence of a mandatory relationship indicates that the minimum cardinality is 0 or 1 for the mandatory entity.

Answer

true

Question 29

29) Relationships operate only in one direction.

Answer

true

Question 30

30. A recursive relationship is one in which a relationship can exist between occurrences of the same entity set

Answer

true

Chapter 4 (True/False)

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