Hibernate 3.0

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Hibernate 3.0
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What is Hibernate

• Hibernate is a free, open source Java package
  that makes it easy to work with relational
  databases.
• Hibernate makes it seem as if your database
  contains plain Java objects like you use every
  day, without having to worry about how to get
  them out of (or back into) mysterious database
  tables.
• Hibernate liberates you to focus on the objects
  and features of your application, without having
  to worry about how to store them or find them
  later.

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Why Hibernate?

• Cost effective.
• Learning is very easy compare to EJB.
• High Performance than EJB
• No more need for JDBC API for Result set
  handling.
• Switching to other SQL database requires few
  changes in Hibernate configuration file

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Advantage of using the Hibernate

• Database independent application
• Avoid writing queries
• Avoid JDBC API completely
• Hibernate uses connection pooling technique
• Automatic Key Generation
• Develop the Application in short Period of time

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Hibernate Support Different Database

• DB2
• MySQL
• PostgreSQL
• Oracle (any version)
• Microsoft SQL Server
• HypersonicSQL
• Informix
• Ingres
• Interbase
• Pointbase
• Mckoi SQL
• Progress
• FrontBase
• SAP DB
• Sybase

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Hibernate Architecture
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Hibernate Architecture

• Hibernate architecture has three main components
  
• Connection Management Hibernate Connection
  management service provide efficient management
  of the database connections. Database connection
  is the most expensive part of interacting with
  the database as it requires a lot of resources of
  open and close the database connection.  
• Transaction management Transaction management
  service provide the ability to the user to
  execute more than one database statements at a
  time.  
• Object relational mapping Object relational
  mapping is technique of mapping the data
  representation from an object model to a
  relational data model. This part of the hibernate
  is used to select, insert, update and delete the
  records form the underlying table. When we pass
  an object to a Session.save() method, Hibernate
  reads the state of the variables of that object
  and executes the necessary query.

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• Hibernate is very good tool as far as object
  relational mapping is concern but in terms of
• connection management and
• transaction management,
• it is lacking in performance and capabilities. So
  usually hibernate is being used with other
  connection management and transaction management
  tools. For example apache DBCP is used for
  connection pooling with the Hibernate.

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Hibernate 3.0

• Hibernate 3.0 provides three full-featured query
  facilities
• Hibernate Query Language
• Hibernate Criteria Query API
• Hibernate Native Query

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Hibernate Criteria Query API

• The Criteria interface allows to create and
  execute object-oriented queries. It is powerful
  alternative to the HQL but has own limitations.
  Criteria Query is used mostly in case of multi
  criteria search screens, where HQL is not very
  effective. 

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Hibernate Native Query

• Native SQL is handwritten SQL for all database
  operations like create, update, delete and
  select. Hibernate Native Query also supports
  stored procedures. Hibernate allows you to run
  Native SQL Query for all the database operations,
  so you can use your existing handwritten sql with
  Hibernate, this also helps you in migrating your
  SQL/JDBC based application to Hibernate.

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How to Implement Hibernate

• Configuring Hibernate
• Persistence Class
• Map the Object to the Database table
• Setting up the Database
• Insert, Update and Delete records in the table
  (Hibernate automatically creates query to perform
  this operations)

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1. Configuring Hibernate

• Hibernate uses the hibernate.cfg.xml to create
  the connection pool and setup required
  environment.
• lthibernate-configurationgtltsession-factorygt   ltpr
  operty name"hibernate.connection.driver_class"gtco
  m.mysql.jdbc.Driver
• lt/propertygt   ltproperty
  name"hibernate.connection.url"gtjdbcmysql//local
  host/hibernate
• lt/propertygt      ltproperty name"hibernate.conne
  ction.username"gtrootlt/propertygt      ltproperty
  name"hibernate.connection.password"gtlt/propertygt 
       ltproperty name"hibernate.connection.pool_siz
  e"gt10lt/propertygt      ltproperty
  name"dialect"gtorg.hibernate.dialect.MySQLDialectlt
  /propertygt      ltproperty name"hibernate.hbm2ddl
  .auto"gtupdatelt/propertygt      lt!-- Mapping files
  --gt      ltmapping resource"contact.hbm.xml"/gtlt/
  session-factorygt
• lt/hibernate-configurationgt

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2. Persistence Class

• Hibernate uses the Plain Old Java Objects (POJO)
  classes to map to the database table. We can
  configure the variables to map to the database
  column.
• package Example
• public class Contact   private String firstName
  private String lastName private String email
  private long id public String getEmail()     
  return email    public String getFirstN
  ame()     return firstName
       public String getLastName()     return l
  astName     public void setEmail(String
   string)     email  string
      public void setFirstName(String string)  
     firstName  string     public void se
  tLastName(String string)     lastName  string
      public long getId()     return id
      public void setId(long l)     id  l
  

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3.Map the Object to the Database table

• The file contact.hbm.xml is used to map Contact
  Object to the Contact table in the database.
• lthibernate-mappinggt  ltclass nameExample.Contact
  " table"CONTACT"gt   ltid name"id" type"long"
  column"ID" gt   ltgenerator class"assigned"/gt 
  lt/idgt  ltproperty name"firstName"gt    
  ltcolumn name"FIRSTNAME" /gt  lt/propertygt 
  ltproperty name"lastName"gt    ltcolumn
  name"LASTNAME"/gt  lt/propertygt  ltproperty
  name"email"gt    ltcolumn name"EMAIL"/gt 
  lt/propertygt lt/classgt
• lt/hibernate-mappinggt

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4.Setting up the Database

• package Example
• import org.hibernate.Session import org.hibernate
  .SessionFactory
• import org.hibernate.cfg.Configuration
• public class FirstExample  
•  public static void main(String args) 
•  Session session  null
•  try
• SessionFactory sessionFactory  new Configuration(
  ).configure().buildSessionFactory()     
   session sessionFactory.openSession()       val
  ues in it by reading them from form object       
  Contact contact  new Contact()        contact.s
  etId(3)        contact.setFirstName(kumar")  
        contact.setLastName(m")        contact.se
  tEmail(kumar.m_at_yahoo.com")        session.save(
  contact)        System.out.println("Done")    
  catch(Exception e)      System.out.println(e.ge
  tMessage())    finally      session.flush()
        session.close()
•     

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Thank you