All Guides04-persistence-data-access
Persistence & Data Access
JPA, transactions, fetch strategies, and query patterns for backend persistence layers.
backend-engineerpersistencejpatransactionsquery
Persistence & Data Access
Build reliable backend storage with correct entity modeling, transaction boundaries, and performance-aware data access.
Key concepts
- Spring Data JPA entity mapping and relationship modeling.
- Transaction propagation and isolation.
- Lazy vs eager fetch strategies and N+1 query avoidance.
- Pagination and criteria-driven query patterns.
Engineering focus
Prevent inefficient queries, keep transactional boundaries explicit, and avoid loading unnecessary data into memory.
Interview Questions
- What is the N+1 query problem and how can you fix it?
- When should you use lazy loading vs eager loading?
- Explain transaction propagation in Spring.
- Why is pagination important for APIs that query large datasets?