Question 1

Referential integrity and participation are both bidirectional, meaning that they must be addressed in both directions along a relationship.

Accepted Answer

Referential integrity primarily concerns ensuring that a foreign key in one table correctly references a primary key in another table, focusing on the unidirectional link from the foreign key to the primary key. Participation, on the other hand, refers to whether entities in a relationship must or may participate in the relationship, which can be considered in both directions but does not inherently require bidirectional enforcement like referential integrity.

Question 2

Relationships between entities always operate in one direction.

Accepted Answer

Relationships between entities can operate in both directions, such as a "has" relationship between a car and its owner, where the owner "has" the car and the car "belongs to" the owner.

Question 3

An entity in the entity relationship model corresponds to a table in the relational environment.

Accepted Answer

In the entity relationship model, an entity represents a set of objects or concepts in the real world that can be identified by common characteristics. In the relational environment, a table also represents a collection of related data entities. Therefore, an entity in the entity relationship model corresponds to a table in the relational environment.

Question 4

Connectivities and cardinalities are established by concise statements known as business rules.

Accepted Answer

Business rules define the relationships between entities and their attributes in a concise statement, establishing connectivities and cardinalities.

Question 5

The Crow's Foot notation easily identifies multivalued attributes.

Accepted Answer

Crow's Foot notation is primarily used for representing relationships in an Entity-Relationship Diagram (ERD), not for identifying multivalued attributes.

Question 6

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

Accepted Answer

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

Question 7

In the original Chen notation, each attribute is represented by an oval with the attribute name connected to an entity rectangle with a line.

Accepted Answer

In the original Chen notation, each attribute is represented by an oval with the attribute name connected to an entity rectangle with a line.

Question 8

The entity relationship model (ERM) is dependent on the database type.

Accepted Answer

The entity relationship model is a conceptual model that describes the relationships between entities in a database, regardless of the specific database type. It is independent of any particular implementation or technology.

Question 9

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

Accepted Answer

A weak entity is dependent on the existence of a related entity and its primary key is partially or totally derived from the parent entity.

Question 10

The Crow's Foot notation is less implementation-oriented than the Chen notation.

Accepted Answer

Crow's Foot notation is more implementation-oriented, focusing on how entities relate to each other in a database, while Chen notation emphasizes a conceptual view of the database structure.

Question 11

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

Accepted Answer

In Chen notation, cardinality is represented by expressing the minimum and maximum number of entity occurrences associated with one occurrence of the related entity.

Question 12

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

Accepted Answer

A weak relationship exists when the related entity does not contain any primary key components of the parent entity; instead, it relies on a foreign key to establish the relationship.

Question 13

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

Accepted Answer

A composite identifier is a primary key composed of more than one attribute. It is used when a single attribute cannot uniquely identify a record in a table.

Question 14

In the Chen and Crow's Foot notations, an entity is represented with a rectangle containing the entity's name.

Accepted Answer

Both the Chen and Crow's Foot notations represent an entity with a rectangle containing the entity's name.

Question 15

In the entity relationship model, a table row corresponds to an entity instance.

Accepted Answer

In the entity relationship model, a table represents an entity set, and each row in the table represents an instance of that entity. Therefore, a table row corresponds to an entity instance.

Question 16

Composite attributes make it easier to facilitate detailed queries.

Accepted Answer

The answer of Composite attributes make it easier to facilitate...

Question 17

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.

Accepted Answer

Yes, this is true. Understanding the cardinality and optionality of relationships is crucial in designing a database schema. This helps determine the appropriate tables and relationships needed to accurately store and retrieve data.

Question 18

In a 1:M relationship, to avoid the possibility of referential integrity errors, the data of the "1" side must be loaded first.

Accepted Answer

This is true as the "1" side of the relationship sets the primary key for the "M" side, and this key needs to exist before any data can be added to the "M" side without causing referential integrity errors.

Question 19

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

Accepted Answer

Software vendors have not widely adopted the Chen representation primarily because it is not as compact as other methods like the Crow's Foot notation, which is more space-efficient and easier to read for complex database structures.

Question 20

In implementation terms, an entity is existence-dependent if it has a mandatory primary key.

Accepted Answer

An entity is existence-dependent if it cannot exist without being related to another entity, not because it has a mandatory primary key.

Quiz 4: Entity Relationship Er Modeling

Referential integrity and participation are both bidirectional, meaning that they must be addressed in both directions along a relationship.

Relationships between entities always operate in one direction.

An entity in the entity relationship model corresponds to a table in the relational environment.

Connectivities and cardinalities are established by concise statements known as business rules.

The Crow's Foot notation easily identifies multivalued attributes.

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

In the original Chen notation, each attribute is represented by an oval with the attribute name connected to an entity rectangle with a line.

The entity relationship model (ERM) is dependent on the database type.

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

The Crow's Foot notation is less implementation-oriented than the Chen notation.

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

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

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

In the Chen and Crow's Foot notations, an entity is represented with a rectangle containing the entity's name.

In the entity relationship model, a table row corresponds to an entity instance.

Composite attributes make it easier to facilitate detailed queries.

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.

In a 1:M relationship, to avoid the possibility of referential integrity errors, the data of the "1" side must be loaded first.

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

In implementation terms, an entity is existence-dependent if it has a mandatory primary key.