Relational database concepts - Quiz

Q: What is a foreign key in a relational database?

A. A key used for sorting data in a table
B. A key used for joining two tables
C. A key that uniquely identifies a row in a table
D. A key that represents a relationship between tables

Correct Option: D
Explanation:

A foreign key is a column or a set of columns in a table that refers to the primary key of another table. It establishes a relationship between two tables by enforcing referential integrity and allowing data to be shared and connected between them.

Q: What is referential integrity in a relational database?

A. The ability to secure and restrict access to sensitive data
B. The process of optimizing data storage and retrieval
C. The practice of maintaining data consistency and correctness
D. The ability to perform complex data calculations and analysis

Correct Option: C
Explanation:

Referential integrity in a relational database refers to the consistency and correctness of the data relationships between tables. It ensures that foreign key values in one table match the primary key values in another table, preventing orphaned records and maintaining data integrity.

Q: What is normalization in the context of relational databases?

A. The process of converting data into binary format for storage
B. The process of optimizing query performance in a database
C. The process of organizing data to eliminate redundancy and dependency
D. The process of securing data from unauthorized access

Correct Option: C
Explanation:

Normalization is the process of structuring and organizing data in a relational database to eliminate data redundancy and minimize data dependency. It involves breaking down larger tables into smaller ones and establishing relationships between them to improve data integrity and flexibility.

Q: What is a transaction in a relational database?

A. A process of connecting to a remote database server
B. A unit of work that consists of multiple database operations
C. A mechanism for generating unique identifiers for new records
D. A method for querying and retrieving data from a database

Correct Option: B
Explanation:

A transaction in a relational database is a unit of work that consists of multiple database operations, such as inserting, updating, or deleting records. It ensures that all the operations are executed as a single, atomic unit, maintaining data consistency and allowing for rollback in case of errors.

Q: What is a many-to-many relationship in a relational database?

A. A relationship where each record in one table is related to multiple records in another table
B. A relationship where each record in one table is related to exactly one record in another table
C. A relationship where multiple records in one table are related to multiple records in another table
D. A relationship where each record in one table is related to zero or one record in another table

Correct Option: C
Explanation:

A many-to-many relationship in a relational database occurs when multiple records in one table can be associated with multiple records in another table. It requires a junction table to connect the related records, typically using the primary keys of both tables.

Q: What is a one-to-many relationship in a relational database?

A. A relationship where each record in one table is related to multiple records in another table
B. A relationship where each record in one table is related to exactly one record in another table
C. A relationship where multiple records in one table are related to multiple records in another table
D. A relationship where each record in one table is related to zero or one record in another table

Correct Option: A
Explanation:

A one-to-many relationship in a relational database occurs when each record in one table can be associated with multiple records in another table. It is the most common type of relationship, often represented by a foreign key in the "many" side table.

Q: What is a view in a relational database?

A. A virtual table derived from the data in one or more tables
B. A temporary storage area for intermediate query results
C. An index structure for faster data retrieval
D. A set of predefined SQL statements for common database operations

Correct Option: A
Explanation:

A view in a relational database is a virtual table that is derived from the data in one or more underlying tables. It acts as a saved SQL query that can be treated and used like a table, providing a convenient way to present specific subsets of data.

Q: Which of the following statements best describes a relational database?

A. A database that stores data in a hierarchical structure
B. A database that stores data in a network structure
C. A database that stores data in tables with relationships between them
D. A database that stores data in a flat file structure

Correct Option: C
Explanation:

A relational database is a type of database management system that organizes and stores data in tables. These tables are related to each other through defined relationships, such as primary keys and foreign keys, enabling efficient data retrieval and manipulation.

Q: What is a primary key in a relational database?

A. A key used for sorting data in a table
B. A key used for joining two tables
C. A key that uniquely identifies a row in a table
D. A key that represents a relationship between tables

Correct Option: C
Explanation:

A primary key is a column or a set of columns in a table that uniquely identifies each row. It ensures that each row in the table has a unique identifier, which is essential for data integrity and efficient data retrieval.

Q: What is the purpose of an index in a relational database?

A. To define a primary key for a table
B. To ensure data integrity
C. To optimize query performance
D. To enforce referential integrity

Correct Option: C
Explanation:

An index in a relational database is a data structure that improves the speed of data retrieval operations, such as searching, sorting, and joining tables. It allows the database engine to locate data more efficiently by creating a separate data structure based on selected columns.