Hibernate 1

Introduction ORM goal: Take advantage of the things SQL databases do well, without leaving the Java language of objects and classes. ORM real goal: Do less work and have a happy DBA. Hibernate is an open-source ORM toolkit for the Java language, providing a framework for mapping an object- oriented domain model to a traditional relational database. 2

Hibernate Architecture 3

XML XML (Extensible Markup Language) is a human readable way of describing structured data. XML is made up of tags enclosing text: David 47 Mapping Java classes to database table is accomplished through the configuration of an XML file. 4

SQL SQL (Structured Query Language) is a standard language for accessing and manipulating relational databases. SQL queries allow the user to specify a description of the desired result set: SELECT title, price FROM Book WHERE price > ORDER BY title SQL is designed for the retrieval and management of data in database and database schema creation and modification. 5

Hibernate query options Hibernate Query Language (HQL) “minimal” object-oriented dialect of ANSI SQL Criteria Queries (QBC) extensible framework for query objects includes Query By Example (QBE) Native SQL queries SQL queries may be defined and called exactly HQL query 6

Hibernate Features Persistence for POJOs (JavaBeans) Flexible and intuitive mapping Support for fine-grained object models Powerful, high performance queries Dual-Layer Caching Architecture (HDLCA) Lazy loading 7