customer_id in Reservation → references Customer.customerId
restaurant_id in Reservation → references
Restaurant.restaurantId
Role in Referential Integrity: Ensures every
reservation links to valid customers and restaurants, prevents
orphaned records, enforces relationships, and enables cascade
operations.
Keywords Found:
Q1210 marks
Explain First Normal Form (1NF) and describe violations that
prevent a relation from being in 1NF.
✓ Model Answer
A relation is in 1NF if all attributes contain only atomic
(indivisible) values.
Explain Second Normal Form (2NF) and the type of functional
dependency that must be eliminated.
✓ Model Answer
A relation is in 2NF if it's in 1NF and every non-prime
attribute is fully functionally dependent on the entire
primary key.
Must eliminate: Partial dependencies
(non-prime attributes depending on part of a composite key).
Keywords Found:
Q1410 marks
Explain Third Normal Form (3NF) and what must be eliminated to
achieve it.
✓ Model Answer
A relation is in 3NF if it's in 2NF and no non-prime attribute
is transitively dependent on the primary key.
Must eliminate: Transitive dependencies (A →
B → C where B is non-prime).
Keywords Found:
💻 SQL Queries
20 marks
▼
Q1510 marks
Write a SQL query to find customers who have placed orders
totaling more than $500.
Schema: Customers (CustomerID, Name), Orders (OrderID, CustomerID,
TotalAmount)
✓ Model Answer
SELECT C.Name, SUM(O.TotalAmount) AS Total FROM Customers C
JOIN Orders O ON C.CustomerID = O.CustomerID GROUP BY
C.CustomerID, C.Name HAVING SUM(O.TotalAmount) > 500;
Keywords Found:
Q1610 marks
Write SQL queries to:
1. List all unique cities where customers live
2. Insert a new customer
3. Update a customer's address
✓ Model Answer
-- 1. Unique cities SELECT DISTINCT City FROM Customers; -- 2.
Insert customer INSERT INTO Customers (CustomerID, Name, City)
VALUES (101, 'John Doe', 'Riyadh'); -- 3. Update address
UPDATE Customers SET Address = '123 Main St' WHERE CustomerID
= 101;