1. New Technology: Why, What ,How
Requirement .
Current way of doing things.
Problem .
Generic Solution or Design Pattern.
Available solutions in market.
Hibernate .
Where to read from ?

2. Typical Requirement App Data Needs to be persisted.
Data generally Outlives Applications.
Application : Object Oriented Language -> Java , C#
Databases : Relational Databases.
Mid-Size App : Around 35% code involves Persistence Layer

3. Current way Domain Model and Schema are Designed Separately.
Tables  Classes Tables.
Transformation: Manual SQL and results are mapped to Objects.
Lots of SQL  Row becomes an Object Instance.
Developers responsibility of mapping OO Instances to Tables row and Column.

4. Problem Object Relational Impedance: Resistance or Obstruction.
1. Structural Problems:
a) Java Types vs. SQL Types.
b) User Defined Types.
c) Inheritance.
2.Behavioral Mismatch :
a) Tables :data ,Objects :data and Behavior .
b) Polymorphism.
c) Equality.
d) Associations.
3. Granularity.
4. Data Navigation.

5. Problem Large Systems : a) Cache Management b) Transaction Handling.
SQL dependent on Underlying DB : Portability ??

6. Constraints :Fundamental Shift
Reason’s why we cant change the way we work.
Move to OO Databases : Gemstone,Db4O
a) RDBMS  backed by Mathematics.
b) Performance in Data Management.
c) Already Huge Investment In RDBMS.
Move away From OO Concepts:
a) We All know benefits of OO principles .
b) Shines in Complex Domain Structure.
So We have to live with Previous Problems.

7. General Solution SOLUTION: Use a mapping layer to map between
Goal : We want to directly manipulate data contained in a relational database using an object programming language (Java).
SOLUTION: Use a mapping layer to map between
the object world and the relational world.
Automate task of converting Tables  Classes Tables.
Framework to optimize I/O transaction's b/w App layer and DB.
Framework having a Cache Management.
Runtime SQL generation :portability across different Db Vendors.
This resulted in number of Home-grown ORM frameworks.

8. Available solutions Language Name Type
Lots of ORM frameworks now available in market.
Language
Name
Type
Java
Hibernate
Open-Source
IBATIS
ASF
Top-Link
Oracle
.NET
NHibernate
Open-source
Genome
commercial

9. Why Hibernate Quite Mature and vast functionality. Open-Source .
Substantial User base.
Heavily influenced JPA specification, Industry approved.
Close to EJB 3 Specification.
Good Caching and Transaction management functionality available.
Support for almost all available Databases.
Learning Curve is Easy:
a) Lots of material on Net.
b) Many Books now available.

10. Resources http://www.hibernate.org/hib_docs/reference/en/html_single/