deleteAll deleteAllbybatch deleteinbatch
querydsl
deleteByaIdx를 진행할 때 aIdx가 없어도 에러가 발생 안하는데
deleteById를 할 때는 id가 존재하지 않으면 에러가 발생하는 이유
save와 saveAll 의 속도 차이가 발생하는 이유
https://www.baeldung.com/spring-data-save-saveall
https://sas-study.tistory.com/388
https://mingg123.tistory.com/m/117
transactional 격리수준
https://velog.io/@kdhyo/JavaTransactional-Annotation-%EC%95%8C%EA%B3%A0-%EC%93%B0%EC%9E%90-26her30h
https://nesoy.github.io/articles/2019-05/Database-Transaction-isolation
https://www.inflearn.com/questions/94056
https://www.inflearn.com/questions/518473