Spring Data JPA entity Relationship

• go to browser localhost:8181/swagger-ui/index.html#/

• Cascade is the feature provided by hibernate to automatically manage the state of mapped entity whenever the state of its relationship owner entity is affected.
• The property cascade = CascadeType. ALL indicates that when we persist, remove, refresh or merge this entity all the entities held in this field would be persist, remove, delete or update.
• Lazy loading in Hibernate means fetching and loading the data, only when it is needed, from a persistent storage like a database. Lazy loading improves the performance of data fetching and significantly reduces the memory footprint.

• go to swagger ui
• add a city
• add a Zipcode
• add a Category
• add an author
• add a book
• go to database at http://localhost:8181/h2