Home› Tutorials› SQL› Database Design Interview Questions

Database Design Interview Questions

All SQL topics
← SQL Best Practices (🎯 Interview & Career Preparation) System Design with SQL →
∙ Topic

Database Design Interview Questions

Database design interview questions test your understanding of schema design, normalization, relationships, indexing, scalability, and real-world system design. These concepts are essential for backend, full-stack, and database developer roles.

📝Syntax
-- Database Design Interview Questions
SELECT 1;
database-design-interview-questions.sql
📝 Edit Code
👁 Preview
💡 This preview does not execute SQL; it’s for reading/editing the query.
💡Database Design Basics
  • 1Understanding entities and attributes.
  • 2Defining relationships.
  • 3Choosing primary keys.
  • 4Identifying constraints.
💡Normalization
  • 11NF: Eliminate repeating groups.
  • 22NF: Remove partial dependency.
  • 33NF: Remove transitive dependency.
  • 4Improves data integrity.
💡Relationships
  • 1One-to-One relationship.
  • 2One-to-Many relationship.
  • 3Many-to-Many relationship.
  • 4Use of junction tables.
💡Indexing Strategy
  • 1Primary index for unique records.
  • 2Secondary indexes for search.
  • 3Composite indexes for complex queries.
  • 4Avoid over-indexing.
💡Scalability Design
  • 1Vertical vs Horizontal scaling.
  • 2Sharding large tables.
  • 3Caching frequently used data.
  • 4Read replicas for performance.
💡Real World Design Use Cases
  • 1ERP system architecture.
  • 2CRM customer tracking systems.
  • 3E-commerce order systems.
  • 4SaaS multi-tenant databases.
  • 5Banking transaction systems.
🏢Real-world
  • 1Used in ERP systems for structured data management.
  • 2Used in CRM for customer relationship tracking.
  • 3Used in SaaS platforms for multi-tenant design.
  • 4Used in banking systems for secure transactions.
  • 5Used in e-commerce platforms for order processing.
⚠Common Mistakes
  • 1Not normalizing tables properly.
  • 2Ignoring foreign key relationships.
  • 3Storing multiple entities in one table.
  • 4Not planning for scalability.
  • 5Missing indexing strategy.
✅Best Practices
  • 1Follow normalization rules (1NF, 2NF, 3NF).
  • 2Use proper primary and foreign keys.
  • 3Design for scalability from start.
  • 4Index frequently queried columns.
  • 5Separate concerns into multiple tables.
✅Quick Summary
  • Database design is the foundation of backend systems.
  • Normalization ensures clean and structured data.
  • Relationships define how tables interact.
  • Indexing improves performance.
  • Scalability must be considered from the beginning.
🎯Interview Questions
Q1. What is normalization?
Answer: Normalization is the process of organizing data to reduce redundancy and improve integrity.
Q2. What is a primary key?
Answer: A primary key uniquely identifies each record in a table.
Q3. What is a foreign key?
Answer: A foreign key creates a relationship between two tables.
Q4. What is denormalization?
Answer: Denormalization is adding redundancy to improve read performance.
Q5. Why is indexing important?
Answer: It improves query performance by reducing data lookup time.
❓Quiz

Which rule removes transitive dependency in database design?

Related topics

Common SQL MistakesDebugging SQL QueriesSQL Best Practices (🎯 Interview & Career Preparation)System Design with SQLFreelancing with SQLRemote Jobs for SQL DevelopersWhat is SQL?History of SQLFeatures of SQLWhy Learn SQL?
←
PreviousSQL Best Practices (🎯 Interview & Career Preparation)
 SQL Tutorial
NextSystem Design with SQL →