Transcript Hibernate_ - JBoss Issue Tracker

Seminar
on
Overview
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Hibernate. What is it?

Hibernate. How does it work?
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Hibernate Tools
Hibernate. What is it?
Definition
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Hibernate is free as open source software

Hibernate is an ORM library for the Java
language, providing a framework for mapping
an object-oriented domain model to a
traditional relational database
Definition
Definition
Creator
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Gavin King
[email protected]
The author of the book «Hibernate in Action»
together with Christian Bauer
The Goals
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To provide automated & optimized
techniques
To reduce the time that developers devote to
manual coding & make them concentrated
more on business logic of their application
(25%)
To insulate two object models
To provide smart fetching & cashing
To supply a toolset for development
Benefits

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
Provides quite
simple model
(fewer LOC)
Rather easy for
learning
Open source
software
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DBMS
independence
Own query
language (HQL)
Hibernate.
How does it work?
All you need for start
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Hibernate distribution (hibernate.org)
Database of your choice (hsqldb preferably)
SQL tables to hold your persistent objects
Java classes to represent that objects in
code
XML mapping files
Configuration file for database connection
settings
Development strategies

Java → Hibernate → Database (top-down)
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Java ← Hibernate ← Database (bottom-up)
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Java ← Hibernate → Database (middle-out)
Persistent Class
package hello;
private class Message{
private Long id;
private String text;
private Message nextMessage;
private Message() {}
public Message(String text){
this.text = text;
}
public Long getId(){
return id;
}
Persistent Class
public void setId(Long id){
this.id = id;
}
public String getText(){
return text;
}
public void setText(String text){
this.text = text;
}
public Message getNextMessage(){
return nextMessage;
}
public void Message(Message nextMessage){
this.nextMessage = nextMessage;
} }
XML Mapping

Tells Hibernate what classes to store in a
database and how they relate to Tables and
Columns
Instead of mappings you can use annotated
classes
XML Mapping
<hibernate-mapping>
<class name=“hello.Message”
table=“MESSAGES”>
<id name=“id”
column=“MESSAGE_ID”>
<generator class=“increment”/>
(assigned, natural)
</id>
<property name=“text”
column=“MESSAGE_TEXT”/>
<many-to-one
name=“nextMessage”
cascade=“all”
column=“NEXT_MESSAGE_ID”/>
</class>
</hibernate-mapping>
Database settings (.cfg.xml)
<hibernate-configuration>
<session-factory>
<property
name="hibernate.connection.driver_class">org.hsqldb.jdbcDriver</pro
perty>
<property
name="hibernate.connection.url">jdbc:hsqldb:hsql://localhost/
</property>
<property
name="hibernate.connection.username">sa</property>
<property
name="dialect">org.hibernate.dialect.HSQLDialect</property>
<mapping resource="hello/Message.hbm.xml"/>
</session-factory>
</hibernate-configuration>
Create Database Table
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Start the database
Create a table
Now it’s time to see Hibernate in action
Work with objects
Work with objects
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Through the Session Hibernate works with a
Database
Transaction involves a unite of work with a
Database
Work with objects
Hibernate Tools
Hibernate Tools
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Toolset for development
Makes working with Hibernate much easier
Comes with JBoss Tools
A part of JBDS
Available both as plugin to Eclipse or via Ant
tasks
Shortly about Ant task

To start using Hibernate Tools via Ant define
the fallowing task:
<taskdef name="hibernatetool"
classname="org.hibernate.tool.ant.Hibernate
ToolTask"
classpathref="project.classpath"/>
Hibernate plugin within Eclipse
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Provides a number of wizards & editors for
smart & simpler work with Hibernate
Allows to watch the structure of mapping
files, execute queries as well as see the
results
All of these features are available through
the Hibernate perspective
Development Wizards
for creating:
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Hibernate Configuration File (.cfg.xml)
Hibernate XML mapping file (.hbm.xml)
Hibernate Console Configuration
Hibernate Reverse Engineering (reveng.xml)
Code Generation
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Make use of it when you need to generate
one kind of artifacts to another
Note :
while generating hbm.xml’s, not all
conversions might be implemented, thus
some hand code editing can be necessary.
Editors
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Hibernate Configuration file editor
Hibernate Mapping file editor
Reveng.xml editor
Hibernate Console Perspective
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Hibernate Configuration view
Mapping Diagram
HQL or Hibernate Criteria editors
Hibernate query result view & Dynamic SQL
translator view
Properties View
Gratitude
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Thanks a lot Vitalii Yemialyanchyk &
Geraskov Dmitrii
Presentation is made with help of the book
“Hibernate in action” & “Hibernate Tools
Reference Guide”