This book is a collection of developer code recipes and best practices for persisting data using Spring, particularly Spring Boot. The book is structured around practical recipes, where each recipe discusses a performance case or performance-related case, and almost every recipe has one or more applications. Mainly, when we try to accomplish something (e.g., read some data from the database), there are several approaches to do it, and, to choose the best way, you have to know the implied trades-off from a performance perspective. You'll see that in the end, all these penalties slow down the application. Besides presenting the arguments that favour a particular choice, the application is written in Spring Boot style, which is quite different from plain Hibernate. Persistence is an essential set of techniques and technologies for accessing and using data, and this book demonstrates that data is mobile regardless of specific applications and contexts. In Java development, persistence is critical in the enterprise, eCommerce, cloud and other transaction-oriented applications. After reading and using this book, you'll have the fundamentals to apply these persistence solutions to your mission-critical enterprise Java applications that you build using Spring. You will: Shape *-to-many associations for best performances. Effectively exploit Spring Projections (DTO). Learn best practices for batching inserts, updates and deletes. Effectively fetch parent and association in a single SELECT. Learn how to inspect Persistent Context content, Dissect pagination techniques (offset and keyset), and Handle queries, locking, schemas, and Hibernate types.