WEEK 3-4 ERD Quiz

What is the primary purpose of an ER diagram?

• To define the security measures of a database

• To represent entities and relationships in a database

• To optimize database performance

• To enforce data integrity rules

Which of the following is NOT a component of an ER diagram?

• Entity

• Attribute

• Relationship

• Index

A primary key is used to:

• Uniquely identify each tuple in a relation

• Define relationships between tables

• Store duplicate data

• Represent foreign keys in a schema

What does "cardinality" describe in an ER diagram?

• The number of attributes in an entity

• The number of tuples in a table

• The number of instances of one entity associated with another

• The strength of a relationship

In an ER model, a weak entity:

• Has no attributes

• Can exist without a strong entity

• Depends on a strong entity and uses a foreign key

• Is the same as a derived attribute

Which of the following is an example of a many-to-many relationship?

• Students and their unique ID numbers

• Books and their authors (where a book can have multiple authors and an author can write multiple books)

• Employees and their supervisors (where an employee has only one supervisor)

• Countries and their capital cities

A foreign key in a relational schema is used to:

• Define a unique identifier for each table

• Create a link between two tables

• Store duplicate records

• Represent attributes in an entity

What is the purpose of mapping an ER model to a relational schema?

• To create SQL queries

• To translate the conceptual model into a logical structure

• To enforce database security

• To normalize data

An attribute that can be divided into smaller parts is called a:

• Derived attribute

• Composite attribute

• Multivalued attribute

• Key attribute

What is the first step in converting an ER diagram to a relational schema?

• Defining primary keys for each table

• Mapping entities to tables

• Identifying foreign keys

• Normalizing the data