A high-performance data access layer must resonate with the underlying database system. Knowing the inner workings of a relational database and the data access frameworks in use can make the difference between a high-performance enterprise application and one that barely crawls.
This video course describes how Hibernate Types and identifier work, as well as the best way to choose a given database type when mapping JPA entities.
Vlad Mihalcea is a Java Champion and one of the top Hibernate ORM project committers. He created the Hypersistence Optimizer tool which scans your application configuration and mappings and tells you what changes you need to do to speed up your data access layer.
He's been answering thousands of questions about Hibernate and JPA on StackOverflow for which he's got gold badges for Hibernate, Java, and JPA tags.
Whenever he finds something interesting, he likes to share it on his personal blog. He believes in Open Source Software, and he thinks every developer should get involved, one way or the other.