intermediate~2h
Relationships & Queries
The module where JPA quietly punishes assumptions carried over from plain SQL. Get lazy vs. eager and the N+1 problem genuinely right here, because it's the most common real-world Spring Boot performance bug.
Learning objectives
- Beginner: Identify whether a given @OneToMany/@ManyToOne mapping defaults to lazy or eager loading.
- Intermediate: Spot a N+1 query problem in application logs and explain why it happened.
- Advanced: Fix an N+1 problem using JOIN FETCH or an @EntityGraph, and justify the trade-off against always eager-loading.
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Relationships & Queries