Hibernate Architecture

Object Relational Mapping

• A DAO can use an ORM framework for persistence tasks.
• ORM framework is written to reduce the efforts done by DAO classes, like database connectivity,
   constructing sql queries etc.
• ORM also improve the performance of DAO layer by providing caching, query optimization etc.
• Even ORM take care of database independency that’s why we do not require using factory method and
   abstract factory pattern at DAO layer for achieving the same.
• DAO was 2 step approach, ORM will be introduced as a 3rd step, see the figure below.
• ORM will provide n number of features that we will see shortly.