Advance Java: ORM/JPA/Hibernate之间的关系

Java Persistence API: JPA.
sounds like ORM: object relational Mapping. but ORM is like an idea, a thought, but JPA is the standard(don’t implement because it’s interface) based on ORM idea, using Java.
Hibernate is one of the framework that implements the idea of ORM.

ORM思想的优点：
encapsulate all the details of data access, don’t need to worry about deal with DB record directly, there will be Java objects for us to manipulate.
ORM思想的缺点：

1. low performance (because of tons of mapping)
2. bad at if we need join tables.

简而言之就是三角关系。