jpa-patterns

原文涵盖的主题

• JPA/Hibernate Patterns
• When to Activate
• Entity Design
• Relationships and N+1 Prevention
• Repository Patterns
• Transactions
• Pagination
• Indexing and Performance

Use for data modeling, repositories, and performance tuning in Spring Boot. Designing JPA entities and table mappings Defining relationships (@OneToMany, @ManyToOne, @ManyToMany) Optimizing queries (N+1 prevention, fetch strategies, projections) Configuring transactions, auditing, or soft deletes Setting up pagination, sorting, or custom repository methods Tuning connection pooling (HikariCP) or second-level caching Enable auditing: Default to lazy loading; use JOIN FETCH in queries when needed Avoid EAGER on collections; use DTO projections for read paths Note: DISTINCT is required when fetch-joining a one-to-many collection — without it, the root entity is duplicated once per child row in the result set. For single-result queries (findById) the duplication is harmless, but for list queries it produces duplicate root objects. Hibernate 6+ applies de-duplication automatically in some cases, but explicit DISTINCT keeps behavior portable and clear. Use projections for lightweight queries: Annotate service methods with @Transactional Use @Transactional(readOnly = true) for read paths to optimize Choose propagation carefully; avoid long-running transactions For cursor-like pagination,

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