Database Schema Design - Best Practices

Designing a good database schema is essential for performance, scalability, and maintainability. Here are the best practices for database schema design, categorized for clarity:

✅ 1. Understand the Business Requirements

  • 📋 Talk to stakeholders: Know what data is critical and how it's used.
  • 🧠 Model real-world entities clearly: Each table should represent one concept (e.g., Customer, Order).

✅ 2. Use Proper Naming Conventions

Practice Example
Use singular table names User, not Users
Use lowercase + underscores user_profile
Be consistent Stick to one pattern

✅ 3. Normalize to At Least 3NF

  • 1NF: No repeating groups/arrays
  • 2NF: Full key dependency
  • 3NF: No transitive dependency

➡ Normalize to avoid redundancy, then denormalize later only if needed for performance.

✅ 4. Use Proper Data Types

  • Use INT for IDs, VARCHAR for text, DATE for dates.
  • Avoid unnecessarily large types (e.g., don’t use VARCHAR(255) for a 3-character code).

✅ 5. Define Primary & Foreign Keys

  • Every table should have a primary key (prefer id with auto-increment or UUID).
  • Use foreign keys to enforce referential integrity.

✅ 6. Indexing Smartly

  • Index columns used in WHERE, JOIN, ORDER BY.
  • Don’t over-index — indexes consume space and slow down writes.

✅ 7. Use Constraints for Data Integrity

Constraint Use
NOT NULL Prevent missing data
UNIQUE Enforce uniqueness
CHECK Validate value range
FOREIGN KEY Maintain relationships

✅ 8. Avoid NULLs Where Possible

  • Avoid nullable columns unless truly optional.
  • Use sensible defaults to reduce NULLs.

✅ 9. Document the Schema

  • Use ER diagrams or schema comments.
  • Keep track of relationships, keys, and constraints.

✅ 10. Design for Scalability

  • Think about future growth (sharding, partitioning).
  • Consider UUIDs if you plan distributed inserts.
  • Use read replicas or caching (Redis) for high-read workloads.

🧠 Bonus Tips

  • Use ENUM for known values (e.g., status: ACTIVE, INACTIVE).
  • Separate audit/log tables from main data.
  • Consider soft deletes using a deleted_at column instead of physically deleting rows.
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