Database Systems Quiz

What is a relational database?

• A relational database is a type of database that does not allow data to be related.

• A relational database is a type of database that stores and provides access to data points that are related to one another.

• A relational database is a type of database that stores data in a non-relational manner.

• A relational database is a type of database that only stores numerical data.

Explain the concept of primary key in a relational database.

• A primary key is used for sorting data in a table

• A primary key uniquely identifies each record in a table and helps in establishing relationships between tables.

• A primary key is not necessary for data integrity in a database

• A primary key can have duplicate values in a table

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

• SELECT * FROM students;

• SELECT * FROM all students;

• SELECT * FROM table students;

• SELECT * FROM student;

What is the purpose of the WHERE clause in SQL queries?

• To sort rows in ascending order

• To join multiple tables together

• To update existing rows in the table

• To filter rows based on a specified condition.

Discuss the difference between INNER JOIN and OUTER JOIN in SQL.

• INNER JOIN compares and combines only the matching rows, whereas OUTER JOIN includes all rows from both tables.

• OUTER JOIN compares and combines only the matching rows

• INNER JOIN includes all rows from both tables

• INNER JOIN combines all rows from both tables