Effective Hibernate with Spring

Explore hibernate entity states and transitions, including new and removed states, and learn when to use or avoid the merge operation to optimize transactions and data access.

Experiment with entity transitions in a spring boot gradle project by adjusting the product service or repository to satisfy the tests for attribute updates and minimal query counts.

Examine eagerly loaded and lazy loaded relationships, the SQL these generate, and how fetch joins and related strategies influence Hibernate and JPA queries, prepping for the next module.

The lecture explains eager fetching in a one-to-many relation, showing how loading a parent can fetch children, and warns about performance issues, urging careful use of lazy loading and projections.

Diagnose lazy initialization exceptions by loading lazily loaded relationships outside a transaction, and explore fixes such as enabling temporary transactions, managing transactions, and rethinking transaction boundaries.

The module recap explains how projections limit data in standard sql and criteria api queries, using Spring Data projections. It emphasizes reduced data transfer and memory use, noting covering indices.

Describe explicit optimistic locking in Hibernate, using lock mode and lock calls to enforce a version check and optional version increment. Compare normal optimistic lock with optimistic force increment.

Recap key concurrency strategies in Hibernate with Spring, including optimistic and pessimistic locking. Examine last update anomalies, version-based and version-less optimistic locking, and parameters of pessimistic locks.

Understand how auto mode flushes pending changes before queries and before committing transactions. In comet mode, changes flush only before commit, and native queries may run without an earlier flush.

Explore Hibernate 5.2 statement batching with a global batch size in Spring, and see how flush affects batch composition and the importance of correct batching configuration.