Database Concepts Quiz

What is an entity-relationship model and how is it used in database design?

• It is a method for organizing files in a computer system

• It is a visual representation of the relationships between entities in a database and is used to define the structure of the database and the relationships between different data entities.

• It is a type of computer virus used to corrupt databases

• It is a tool for creating animations in database design

Explain the difference between an entity and an attribute in the context of the entity-relationship model.

• An attribute is a type of entity

• An entity is a type of attribute

• An entity and an attribute are the same thing

• An entity represents a real-world object or concept, while an attribute represents a property or characteristic of that entity.

What are the cardinality and modality constraints in an entity-relationship model?

• They refer to the location and weight of the entities

• They refer to the color and size of the entities

• They refer to the number of instances of one entity that can be associated with the number of instances of another entity and whether the relationship between entities is mandatory or optional.

• They refer to the age and gender of the entities

Describe the process of normalizing a database and why it is important in database design.

• It is important in order to minimize data redundancy, improve data integrity, and optimize database performance.

• It is only important for small databases, not large ones

• It is not important, as it does not affect data integrity

• It is important for increasing data redundancy and decreasing data integrity

Write a SQL query to retrieve all the records from a table named 'students'.

• SELECT * FROM students;

• GET FROM students

• RETRIEVE * FROM students

• SELECT ALL students

Explain the purpose of the 'GROUP BY' clause in SQL and provide an example.

• The 'GROUP BY' clause in SQL is used to sort the data in ascending order

• The 'GROUP BY' clause in SQL is used to filter the data based on a condition

• The 'GROUP BY' clause in SQL is used to update the data in a table

• The purpose of the 'GROUP BY' clause in SQL is to group rows that have the same values and it is often used with aggregate functions.

What is a primary key and why is it important in database design?

• A primary key is a field that can have duplicate values in a database table. It is important in database design because it allows for easy data manipulation.

• A primary key is a secondary identifier for each record in a database table. It is important in database design because it helps in data duplication.

• A primary key is a unique identifier for each record in a database table. It is important in database design because it ensures that each record is uniquely identifiable and helps in maintaining data integrity.

• A primary key is a random number assigned to each record in a database table. It is important in database design because it helps in sorting the records.

Discuss the concept of data redundancy and how it can be minimized in database design.

• Normalizing the database

• Denormalizing the database

• Ignoring data redundancy

• Adding more redundant data

Explain the difference between logical and physical database design.

• Logical database design and physical database design are essentially the same and can be used interchangeably.

• Logical database design involves specific storage structures and access methods, while physical database design does not consider these aspects.

• Logical database design focuses on the structure and organization of data without considering the physical implementation, while physical database design involves the actual implementation of the database using specific storage structures and access methods.

• Logical database design focuses on the physical implementation of the database, while physical database design focuses on the structure and organization of data.

What are the different types of relationships that can exist between tables in a database design?

• One-to-One, One-to-Many, Many-to-Many

• Red, Blue, Green

• Up, Down, Left

• Cat, Dog, Bird