Why SQL security awareness matters - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select all columns from the users table.

SQL

SELECT [1] FROM users;

Drag options to blanks, or click blank then click option'

AEVERY

BCOLUMNS

CALL

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using keywords like ALL or COLUMNS which are not valid here.

The asterisk (*) selects all columns from the table.

2fill in blank

medium

Complete the code to filter users with admin role.

SQL

SELECT * FROM users WHERE role = [1];

Drag options to blanks, or click blank then click option'

Aadmin

B'admin'

C"admin"

DADMIN

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around string values.

String values in SQL must be enclosed in single quotes.

3fill in blank

hard

Fix the error in the SQL query to prevent SQL injection by using a parameter placeholder.

SQL

SELECT * FROM users WHERE username = [1];

Drag options to blanks, or click blank then click option'

A?

B'user_input'

C:username

D$username

Attempts:

3 left

💡 Hint

Common Mistakes

Directly inserting user input as a string.

Using a question mark (?) is a common placeholder for parameters in prepared statements to prevent SQL injection.

4fill in blank

hard

Fill both blanks to create a query that selects usernames and emails only for active users.

SQL

SELECT [1], [2] FROM users WHERE status = 'active';

Drag options to blanks, or click blank then click option'

Ausername

Bemail

Cpassword

Did

Attempts:

3 left

💡 Hint

Common Mistakes

Selecting password or id which may expose sensitive info.

We select only the username and email columns to avoid exposing sensitive data like passwords.

5fill in blank

hard

Fill all three blanks to write a query that updates a user's password securely using a placeholder and limits update to a specific user id.

SQL

UPDATE users SET password = [1] WHERE id = [2] AND role != [3];

Drag options to blanks, or click blank then click option'

A?

B123

C'admin'

D'user'

Attempts:

3 left

💡 Hint

Common Mistakes

Hardcoding password directly, not using placeholders, or updating admin users.

Use a placeholder (?) for the new password to avoid injection, specify the user id (123), and exclude admin role from update.

Practice

1. Why is it important to be aware of SQL security when managing a database?

easy

A. To protect sensitive data from unauthorized access

B. To make queries run faster

C. To reduce the size of the database

D. To increase the number of users who can access the database

Solution

1. Step 1: Understand the purpose of SQL security

   SQL security is designed to protect data from unauthorized users who might misuse or steal it.

2. Step 2: Identify the correct reason for security awareness

   Protecting sensitive data is the main goal, not improving speed or increasing users.

3. Final Answer:

   To protect sensitive data from unauthorized access -> Option A

4. Quick Check:

   SQL security = protect data [OK]

Hint: Security means protecting data from wrong users [OK]

Common Mistakes:

• Confusing security with performance
• Thinking security increases user count
• Believing security reduces database size

2. Which SQL command is used to give a user permission to access a database object?

easy

A. REVOKE

B. GRANT

C. DELETE

D. SELECT

Solution

1. Step 1: Recall SQL commands for permissions

   GRANT is used to give permissions, REVOKE removes them.

2. Step 2: Identify the command that gives access

   GRANT allows users to access or modify database objects.

3. Final Answer:

   GRANT -> Option B

4. Quick Check:

   GRANT = give permission [OK]

Hint: GRANT gives permission, REVOKE takes it away [OK]

Common Mistakes:

• Confusing GRANT with REVOKE
• Using DELETE or SELECT as permission commands
• Thinking SELECT grants permissions

3. Consider this SQL command:
REVOKE UPDATE ON employees FROM user_john;
What is the effect of this command?

medium

A. User John is granted update permission on employees

B. User John can update the employees table

C. User John is deleted from the database

D. User John can no longer update the employees table

Solution

1. Step 1: Understand the REVOKE command

   REVOKE removes permissions previously given to a user.

2. Step 2: Apply to the given command

   This command removes the UPDATE permission on the employees table from user_john.

3. Final Answer:

   User John can no longer update the employees table -> Option D

4. Quick Check:

   REVOKE UPDATE = remove update rights [OK]

Hint: REVOKE removes permission, so user loses update rights [OK]

Common Mistakes:

• Thinking REVOKE grants permission
• Confusing REVOKE with DELETE user
• Assuming REVOKE affects all permissions

4. You run this SQL command:
GRANT SELECT, INSERT employees TO user_anna;
But it returns an error. What is the likely problem?

medium

A. The keyword TO is missing

B. The table name is incorrect

C. The keyword ON is missing before the table name

D. User_anna does not exist

Solution

1. Step 1: Check correct GRANT syntax

   The correct syntax is: GRANT privileges ON table TO user;

2. Step 2: Identify missing keyword

   The command misses ON before the table name employees.

3. Final Answer:

   The keyword ON is missing before the table name -> Option C

4. Quick Check:

   GRANT syntax requires ON before table [OK]

Hint: GRANT needs ON before table name [OK]

Common Mistakes:

• Omitting ON keyword
• Confusing TO placement
• Assuming user existence causes syntax error

5. A database admin wants to ensure that a user can only read data but not change it. Which SQL command should they use?

hard

A. GRANT SELECT ON database TO user_name;

B. GRANT UPDATE ON database TO user_name;

C. REVOKE SELECT ON database FROM user_name;

D. GRANT DELETE ON database TO user_name;

Solution

1. Step 1: Identify read-only permission

   SELECT permission allows reading data without changing it.

2. Step 2: Choose the command granting only read access

   GRANT SELECT ON database TO user_name; gives read-only access.

3. Final Answer:

   GRANT SELECT ON database TO user_name; -> Option A

4. Quick Check:

   SELECT = read-only permission [OK]

Hint: Use GRANT SELECT for read-only access [OK]

Common Mistakes:

• Granting UPDATE or DELETE instead of SELECT
• Revoking SELECT instead of granting
• Granting all permissions accidentally