Here are the top 20 database testing interview questions and answers:
1) What is database testing?
Database testing is a process of verifying the functionality, performance, and reliability of a database. It involves checking data integrity, consistency, and accuracy.
2) What are the different types of database testing?
The different types of database testing include functional testing, performance testing, security testing, scalability testing, and data integrity testing.
3) What is data integrity testing?
Data integrity testing ensures that data is accurate, consistent, and reliable. It involves verifying constraints, relationships, and rules defined in the database schema.
4) What is SQL injection?
How can it be prevented? SQL injection is a technique used by attackers to insert malicious SQL statements into an application’s database query. To prevent SQL injection, use parameterized queries or prepared statements, input validation, and escape special characters.
5) What is a stored procedure?
A stored procedure is a set of SQL statements that are stored in the database and can be executed repeatedly. It is used to encapsulate logic and improve performance.
6) What is normalization in database testing?
Normalization is a process of organizing data in a database to eliminate redundancy and improve data integrity. It involves dividing large tables into smaller ones and defining relationships between them.
7) What is the difference between primary key and unique key?
A primary key is used to uniquely identify a record in a table and cannot contain duplicate or null values. A unique key, on the other hand, allows null values but does not allow duplicate values.
8) What is the purpose of the ACID properties in database testing?
The ACID properties (Atomicity, Consistency, Isolation, Durability) ensure that database transactions are reliable and maintain data integrity. They define the properties that guarantee the success or failure of a transaction.
9) What is the difference between a database and a data warehouse?
A database is a collection of related data organized and structured for efficient retrieval, storage, and management. A data warehouse, on the other hand, is a large repository of data collected from various sources for analysis and reporting.
10) How do you test database performance?
To test database performance, you can use techniques like load testing, stress testing, and performance monitoring. Measure response times, throughput, and resource utilization to identify bottlenecks and optimize performance.
11) What is a deadlock in database testing?
A deadlock occurs when two or more processes or transactions are waiting for each other to release resources, resulting in a standstill. It can be detected and resolved using techniques like deadlock detection algorithms and resource scheduling.
12) What is data migration testing?
Data migration testing is the process of validating the successful transfer of data from one system to another. It involves verifying data integrity, accuracy, and completeness after the migration process.
13) What is the purpose of a database schema?
A database schema defines the structure, organization, and relationships of a database. It includes tables, fields, constraints, and indexes that define how data is stored and accessed.
14) What is the difference between a clustered and a non-clustered index?
A clustered index determines the physical order of data in a table, and there can be only one clustered index per table. A non-clustered index is a separate structure that provides a faster access path to the data but does not determine the physical order.
15) What is the difference between a backup and a restore in database testing?
A backup is a process of creating a copy of the database or its components for disaster recovery or data preservation. A restore is the process of retrieving the backup and returning the database to its previous state.
16) How would you test data accuracy in a database?
To test data accuracy, you can compare the data in the database with the expected values or use data profiling techniques. Validate data against business rules, conduct data integrity checks, and reconcile data from different sources.
17) What is a database trigger?
A database trigger is a set of actions that are automatically performed when a specific event occurs in a database. Triggers are used to maintain data integrity, enforce business rules, or perform automated tasks.
18) What is the purpose of referential integrity in database testing?
Referential integrity ensures that relationships between tables are maintained correctly. It enforces the consistency and validity of data by defining constraints such as foreign key relationships.
19) What are some common database testing tools?
Some common database testing tools include SQL Server Management Studio (SSMS), Oracle SQL Developer, MySQL Workbench, DbUnit, and JUnit.
20) What are some important considerations for database security testing?
Important considerations for database security testing include testing user access controls, encryption, authentication mechanisms, database permissions, vulnerability scanning, and auditing.
These are just a few sample questions and answers to help you prepare for a database testing interview. Make sure to go deeper into each topic and practice hands-on exercises to gain a thorough understanding.
