Understanding Entity Relationships

What is an entity in the context of a data model?

• A physical object or concept

• A type of relationship

• A property of an object

• A database constraint

What does an attribute represent?

• A property or characteristic of an entity

• A relationship between entities

• A unique identifier for an entity

• A type of data model

What is a composite key?

• A set of attributes that uniquely identify an entity

• A type of relationship

• An attribute of an entity

• A diagram representation

What does cardinality refer to in a relationship?

• The number of instances associated between entities

• The type of relationship

• The attributes of an entity

• The uniqueness of an entity

What is a one-to-many relationship?

• One instance of an entity associated with many instances of another

• One instance of an entity associated with one instance of another

• Many instances of an entity associated with one instance of another

• Many instances of an entity associated with many instances of another

What does the line in an E-R diagram represent?

• The cardinality of the relationship

• The attributes of the entities

• The entities themselves

• The type of data model

What is a foreign key?

• A property of an entity

• An attribute that uniquely identifies a record in a table

• A type of data model

• An attribute that creates a link between two tables

What does normalization aim to achieve in a database?

• Decrease the number of relationships

• Reduce data redundancy and improve data integrity

• Enhance the speed of data retrieval

• Increase the number of tables

What is a primary key?

• A type of relationship between tables

• A diagram representation of data

• An attribute that can have multiple values

• An attribute that uniquely identifies each record in a table

What is the purpose of a unique constraint in a database?

• To allow duplicate values in a column

• To ensure all values in a column are unique

• To define a relationship between tables

• To increase the speed of data retrieval