14. Creating Fetch Plans with Entity Graphs
This chapter explains how to use entity graphs to create fetch plans for Java Persistence API operations and queries.
Entity graphs are templates for a particular Persistence query or operation. They are used when creating fetch plans, or groups of persistent fields that are retrieved at the same time. Application developers use fetch plans to group together related persistent fields to improve runtime performance.
By default, entity fields or properties are fetched lazily. Developers specify fields or properties as part of a fetch plan, and the persistence provider will fetch them eagerly.
For example, an email application that stores messages as
EmailMessage entities prioritizes fetching some fields ...