1. Hibernate one to one , one to many and many to many mappings in effective way https://vladmihalcea.com/the-best-way-to-use-the-manytomany-annotation-with-jpa-and-hibernate/ https://vladmihalcea.com/the-best-way-to-map-a-onetoone-relationship-with-jpa-and-hibernate/ https://vladmihalcea.com/the-best-way-to-map-a-onetomany-association-with-jpa-and-hibernate/ Some of the hibernate and JPA property spring.h2.console.enabled=true - to enable h2 in memory database spring.jpa.show-sql=true  - to see all the query in logs spring.jpa.properties.hibernate.format_sql=true - to see all sql in proper format logging.level.org.hibernate.type=trace