Master Hibernate and JPA with Spring Boot in 100 Steps - Step 12 - Entity Manager Methods - clear and detach

The video tutorial explains the role of an entity manager in managing transactions, including persisting and merging entities. It demonstrates creating and persisting courses, using the flush method to send changes to the database, and detaching entities to stop tracking changes. The tutorial also covers clearing the entity manager to stop tracking all entities.

What is the primary role of an entity manager within a transaction?

• To handle network connections

• To track and persist changes to entities

• To manage user sessions

• To manage application logs

In the course management example, what happens when you call 'entity manager dot persist'?

• The course is deleted from the database

• The course is ignored by the entity manager

• The course is temporarily stored in memory

• The course is tracked and changes are persisted to the database

Which method allows you to send changes to the database at specific points in a transaction?

• entity manager dot flush

• entity manager dot clear

• entity manager dot detach

• entity manager dot merge

What is the effect of using the 'detach' method on an entity?

• The entity is no longer tracked by the entity manager

• The entity is updated with default values

• The entity is permanently deleted

• The entity is duplicated in the database

What happens to the changes made to an entity after it has been detached?

• Changes are not tracked or saved

• Changes are tracked but not saved

• Changes are reverted to the original state

• Changes are automatically saved to the database

If you want to stop tracking all entities in the entity manager, which method should you use?

• entity manager dot persist

• entity manager dot merge

• entity manager dot detach

• entity manager dot clear

What is the default behavior of the entity manager regarding entity tracking?

• It tracks entities based on user permissions

• It tracks all entities by default

• It only tracks entities with specific annotations

• It tracks no entities by default