Database Management Systems Unit II Quiz

What is the primary purpose of the relational model in databases?

• Organize data in tables

• Create graphical representations

• Perform complex calculations

• Manage network connections

What is a database schema?

• A visual representation of database tables

• A set of rules for database normalization

• A collection of database objects, including tables and relationships

• A database backup file

In the context of a relational database, what is a key?

• A physical lock securing the database server

• A unique identifier for a record in a table

• A type of encryption algorithm

• A graphical representation of data relationships

What does a schema diagram visually represent?

• Database operations

• Table structures and their relationships

• SQL queries

• Database security measures

Which of the following is a fundamental relational algebra operation?

• Join

• Aggregate

• Project

• Update

What is the purpose of the SELECT operation in relational algebra?

• Combine rows from different tables

• Filter rows based on a condition

• Add new records to a table

• Sort the table in ascending order

Which additional relational algebra operation is used to combine rows from two tables?

• Union

• Join

• Project

• Intersect

What is the purpose of the EXTEND operation in extended relational algebra?

• Add new attributes to a table

• Remove existing attributes from a table

• Create a new table

• Sort the table in descending order

How are null values represented in a relational database?

• As the number 0

• As an empty string

• As a special marker or indicator

• Null values are not allowed in relational databases

What does the term "modification of the database" refer to?

• Querying the database

• Updating, inserting, or deleting records in the database

• Changing the database schema

• Creating a backup of the database