IM2 Midterm exam

What is an Entity Relationship Diagram (ERD)?

• A graphical representation of entities and their relationships in a database system.

• A diagram that shows the flow of data between entities in a system.

• A diagram that shows the hierarchy of entities in a system.

• A diagram that shows the business processes in a system.

What is an entity in an ERD?

• A data type used in a database system.

• A person, place, or thing about which data is stored.

• A connection between two entities in a system.

• A set of rules used to govern data in a system.

What is a relationship in an ERD?

• A data type used in a database system.

• A person, place, or thing about which data is stored.

• A connection between two entities in a system.

• A set of rules used to govern data in a system.

What is a cardinality in an ERD?

• The number of attributes in an entity.

• The number of entities in a database system.

• The number of relationships between entities.

• The number of instances of one entity that can be associated with instances of another entity.

What is an attribute in an ERD?

• A data type used in a database system.

• A person, place, or thing about which data is stored.

• A connection between two entities in a system.

• A property or characteristic of an entity.

What is a primary key in an ERD?

• An attribute that uniquely identifies an entity.

• A connection between two entities in a system.

• A rule that governs the behavior of data in a system.

• A type of data that is used in a database system.

What is a foreign key in an ERD?

• An attribute that uniquely identifies an entity.

• A connection between two entities in a system.

• A rule that governs the behavior of data in a system.

• An attribute in one entity that refers to the primary key of another entity.

What is a weak entity in an ERD?

• An entity that does not have a primary key.

• An entity that is not related to any other entities in a system.

• An entity that has only one attribute.

• An entity that has a primary key that is also a foreign key.

What is an associative entity in an ERD?

• An entity that is used to associate two or more other entities.

• An entity that has only one attribute.

• An entity that is not related to any other entities in a system.

• An entity that does not have a primary key.

What is meant by the term "one-to-one" cardinality in an ERD?

• Each entity in one entity set is associated with zero or one entity in another entity set

• Each entity in one entity set is associated with exactly one entity in another entity set

• Each entity in one entity set is associated with one or more entities in another entity set

• None of the above