What Is Database Testing?

Database testing is the process of validating backend data stored in databases to ensure accuracy, integrity, consistency, and performance. In companies like Capgemini, database testing is critical because most enterprise applications (banking, insurance, healthcare, retail) are data-driven.

Why Database Testing Is Used

Ensures data accuracy between UI and database
Validates business rules at DB level
Prevents data corruption during CRUD operations
Confirms performance & security of queries

👉 This is why database testing interview questions in Capgemini focus heavily on SQL, joins, constraints, and real-time scenarios.

Step-by-Step DB Testing Process

Understand Business Rules
Verify Schemas & Tables
Validate Constraints (PK, FK, UNIQUE)
CRUD Operations Testing
Stored Procedure & Trigger Validation
Data Migration Testing
Performance & Index Validation

Objects Tested

Object	Purpose
Tables	Store application data
Views	Filtered data access
Indexes	Query performance
Triggers	Auto actions
Stored Procedures	Business logic
Functions	Reusable calculations

Database Testing Interview Questions in Capgemini (100+ Q&A)

Basic Database Testing Interview Questions (1–20)

1. What is database testing?

Database testing validates data correctness, schema, constraints, and backend logic using SQL queries.

2. Why is database testing important in Capgemini projects?

Capgemini handles large enterprise systems where data accuracy is business-critical.

3. What are CRUD operations?

Create – INSERT
Read – SELECT
Update – UPDATE
Delete – DELETE

4. What is a primary key?

A column that uniquely identifies each record.

5. What is a foreign key?

A column that references a primary key in another table.

6. Difference between DELETE and TRUNCATE?

DELETE	TRUNCATE
Can rollback	Cannot rollback
Where clause allowed	No WHERE
Slower	Faster

7. What is data integrity?

Ensuring data is accurate and consistent across tables.

8. What is a constraint?

Rules applied to table columns (NOT NULL, UNIQUE).

9. What is a schema?

Logical container for DB objects.

10. What is normalization?

Process of reducing redundancy.

SQL Interview Questions for Testing (21–45)

21. Write a query to fetch all employees.

SELECT * FROM employees;

22. Fetch employees with salary > 50000.

SELECT * FROM employees WHERE salary > 50000;

23. Difference between WHERE and HAVING?

WHERE	HAVING
Filters rows	Filters groups
Used before GROUP BY	Used after GROUP BY

24. GROUP BY example

SELECT department, COUNT(*)

FROM employees

GROUP BY department;

25. HAVING example

SELECT department, COUNT(*)

FROM employees

GROUP BY department

HAVING COUNT(*) > 5;

26. What is an index?

Improves query performance.

27. Types of indexes?

Clustered
Non-clustered
Composite

28. What is JOIN?

Used to combine data from multiple tables.

JOIN-Based Database Testing Interview Questions (46–65)

46. Types of joins?

INNER
LEFT
RIGHT
FULL

47. INNER JOIN example

SELECT e.name, d.dept_name

FROM employee e

INNER JOIN department d

ON e.dept_id = d.id;

48. LEFT JOIN use case?

Fetch all records from left table even if no match exists.

49. Scenario: Validate customer orders

SELECT c.name, o.order_id

FROM customers c

LEFT JOIN orders o

ON c.id = o.customer_id;

50. What is self join?

Joining a table with itself.

Stored Procedures & Triggers (66–80)

66. What is a stored procedure?

Precompiled SQL code stored in DB.

67. Stored procedure example

CREATE PROCEDURE getEmployee(IN emp_id INT)

BEGIN

SELECT * FROM employee WHERE id = emp_id;

END;

68. How do testers validate stored procedures?

Input validation
Output correctness
Exception handling

69. What is a trigger?

Auto-executed SQL on INSERT/UPDATE/DELETE.

70. Trigger example

CREATE TRIGGER log_update

AFTER UPDATE ON employee

FOR EACH ROW

INSERT INTO audit_log VALUES (NEW.id, NOW());

Scenario Based Database Testing Questions (81–95)

81. Scenario: Validate bank transaction balance

Debit entry exists
Credit entry exists
Balance updated correctly

SELECT balance FROM accounts WHERE acc_id=101;

82. Scenario: Data mismatch between UI and DB

Check commit
Validate rollback
Check transaction isolation

83. Scenario: Duplicate records issue

SELECT email, COUNT(*)

FROM users

GROUP BY email

HAVING COUNT(*) > 1;

84. Scenario: Validate soft delete

SELECT * FROM users WHERE is_active=’N’;

Advanced DB Validation Questions (96–115)

96. What is transaction?

Group of SQL statements executed as a unit.

97. ACID properties?

Atomicity
Consistency
Isolation
Durability

98. What is deadlock?

Two transactions waiting for each other.

99. How to test indexes?

Query execution time
Explain plan

100. Explain EXPLAIN plan.

Used to analyze query performance.

Real-Time Use Cases in Capgemini Projects

🏦 Banking Domain

Transaction validation
Balance consistency
Audit logs testing

🏥 Healthcare

Patient data integrity
HIPAA compliance
History tracking

🛒 E-commerce

Order vs payment validation
Inventory count
Refund reconciliation

Common Mistakes Testers Make

Ignoring rollback scenarios
Not validating NULL values
Skipping negative test cases
Not testing performance
Assuming UI validation is enough

Quick Revision Sheet

✔ CRUD operations
✔ JOIN types
✔ GROUP BY & HAVING
✔ Stored procedures
✔ Triggers
✔ Indexes
✔ Transactions

FAQs – Database Testing Interview Questions in Capgemini

Q1. Is SQL mandatory for Capgemini testing roles?
Yes, SQL is mandatory for backend validation.

Q2. Are scenario-based questions common?
Yes, Capgemini focuses heavily on real-time DB scenarios.

Q3. Which DBs are commonly used?
Oracle, MySQL, SQL Server, PostgreSQL.