APPLICATIONS PRACTICE QUESTIONS 2026
◉ What is a tuple in a relational database? Answer: an ordered
collection of elements enclosed in parentheses (a, b, c)
◉ in a relational data structure, which components are named?
Answer: data type, table, and column
rows are NOT named
◉ relational operations: select Answer: selects a subset of rows of a
table
Select *
FROM Employee
WHERE Salary > 50000;
◉ relational operations: project Answer: eliminates one or more
columns of a table
SELECT Name
,FROM Employee;
◉ relational operations: product Answer: lists all combinations of
rows of two tables
SELECT *
FROM Employee, Department;
◉ relational operations: join Answer: combines two tables by
comparing related columns
SELECT *
FROM Employee, Department
WHERE Employee . DeptCode =
Department . DeptCode;
◉ relational operations: union Answer: selects all rows of two tables
◉ relational operations: intersect Answer: selects rows common to
two tables
◉ relational operations: difference Answer: selects rows that appear
in one table but not another
, ◉ relational operations: rename Answer: changes a table name
◉ relational operations: aggregate Answer: computes functions over
multiple table rows such as sum and count
◉ binary values are represented how in SQL syntax Answer: x '0'
The 0 is any hex value
◉ SQL language is divided into five sublanguages Answer: Data
Definition Language (DDL)
Data Query Language (DQL)
Data Manipulation Language (DML)
Data Control Language (DCL)
Data Transaction Language (DTL)
◉ DDL (Data Definition Language) Answer: DDL creates, alters, and
drops tables
ex. Create a table product