TUTIORALS FROM MADHAV:
Hibernate 3.0 example programs by madhav:
Ex1: this is simple hibernate example program that describes
keeping
Department class as persist.
Department.java
package madhav;
import
javax.persistence.Entity;
import
javax.persistence.Id;
@Entity
public class Department {
@Id
private int deptno;
private String dname;
private String loc;
public int getDeptno() {
return deptno;
}
public void setDeptno(int deptno) {
this.deptno = deptno;
}
public String getDname() {
return dname;
}
public void setDname(String dname) {
this.dname = dname;
}
public String getLoc() {
return loc;
}
public void setLoc(String loc) {
this.loc = loc;
}
}
@Entity:
Specifies that the class is an entity. This annotation is applied to the
entity class.
Since:
Java Persistence 1.0
@Id
Specifies the primary key of an entity. The field or property to which the Id annotation is applied should be one
of the following types: any Java primitive type; any primitive wrapper type; String; java.util.Date; java.sql.Date;
java.math.BigDecimal; java.math.BigInteger.
Since:
Java Persistence 1.0
hibernate.cfg.xml
<?xml
version='1.0' encoding='UTF-8'?>
<!DOCTYPE
hibernate-configuration PUBLIC
"-//Hibernate/Hibernate
Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<!-- Generated by MyEclipse Hibernate Tools. -->
<hibernate-configuration>
<session-factory>
<property name="dialect">org.hibernate.dialect.Oracle9Dialect</property>
<property name="connection.url">jdbc:oracle:thin:@localhost:1521:XE</property>
<property name="connection.username">system</property>
<property name="connection.password">system</property>
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto">create</property>
<mapping class="madhav.Department"
/>
</session-factory>
</hibernate-configuration>
TestCase.java
package madhav;
import
org.hibernate.SessionFactory;
import
org.hibernate.Transaction;
import
org.hibernate.cfg.AnnotationConfiguration;
import
org.hibernate.classic.Session;
public class TestCase {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
try {
// Create the SessionFactory from hibernate.cfg.xml
SessionFactory sf= new
AnnotationConfiguration().configure().buildSessionFactory();
Session s=sf.openSession();
Transaction tx=s.beginTransaction();
Department d=new Department();
d.setDeptno(1);
d.setDname("sales");
d.setLoc("hyd");
s.save(d);
tx.commit();
} catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
System.err.println("Initial SessionFactory creation failed." +
ex);
}
}
}
Output in console:
Hibernate: insert into Department (dname, loc, deptno) values (?,
?, ?)
In sqlprompt:
Sql> select * from Department;
DEPTNO
|
DNAME
|
LOC
|
1
|
sales
|
hyd
|
Problem
of Inheritance:
a) Class hirerchy
Employee.java
package madhav;
import
javax.persistence.Entity;
import
javax.persistence.*;
@Entity
@Table(name="employeeinfo")
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(
name="discriminator",
discriminatorType=DiscriminatorType.STRING
)
@DiscriminatorValue(value="e")
public class Employee {
@Id
private int empno;
private String ename;
public int getEmpno() {
return empno;
}
public void setEmpno(int empno) {
this.empno = empno;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
}
@Table
Specifies the primary table for the annotated entity
Ex: @Table(name="employeeinfo")
Defines the inheritance strategy to be used for an entity class hierarchy. It is specified on the entity class that is the root of the entity class hierarchy. If the
Inheritance
annotation is not specified or if no inheritance type is specified for an
entity class hierarchy, the SINGLE_TABLE
mapping strategy is used.
Ex: @Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn
Specifies the discriminator column for the SINGLE_TABLE and JOINED
Inheritance mapping
strategies. The strategy and the discriminator column are only specified in the root of an entity class hierarchy or subhierarchy in which a different inheritance strategy is applied
If the
DiscriminatorColumn
annotation is missing, and a discriminator column is required, the name of the
discriminator column defaults to "DTYPE"
and the discriminator type to DiscriminatorType.STRING.
Ex: @DiscriminatorColumn(
name="discriminator",
discriminatorType=DiscriminatorType.STRING
)
@
DiscriminatorValueSpecifies the value of the discriminator column for entities of the given type.
The
DiscriminatorValue
annotation can only be specified on a concrete entity class. If the
DiscriminatorValue
annotation is not specified and a discriminator column is used, a
provider-specific function will be used to generate a value representing the
entity type. If the DiscriminatorType
is STRING, the discriminator
value default is the entity name. The inheritance strategy and the discriminator column are only specified in the root of an entity class hierarchy or subhierarchy in which a different inheritance strategy is applied. The discriminator value, if not defaulted, should be specified for each entity class in the hierarchy
Ex:
@DiscriminatorValue(value="e")
SalariedEmployee.java
package madhav;
import
javax.persistence.DiscriminatorValue;
import
javax.persistence.*;
@Entity
@Table(name="employeeinfo")
@DiscriminatorValue("se")
public class
SalariedEmployee extends Employee {
public double annualSal;
public double getAnnualSal() {
return annualSal;
}
public void setAnnualSal(double annualSal) {
this.annualSal = annualSal;
}
}
hibernate.cfg.xml
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE
hibernate-configuration PUBLIC
"-//Hibernate/Hibernate
Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<!-- Generated by MyEclipse Hibernate Tools. -->
<hibernate-configuration>
<session-factory>
<property name="dialect">org.hibernate.dialect.Oracle9Dialect</property>
<property name="connection.url">jdbc:oracle:thin:@localhost:1521:XE</property>
<property name="connection.username">system</property>
<property name="connection.password">system</property>
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto">create</property>
<mapping class="madhav.Employee"
/>
<mapping class="madhav.SalariedEmployee"/>
</session-factory>
</hibernate-configuration>
TestCase.java
package madhav;
import
org.hibernate.SessionFactory;
import
org.hibernate.Transaction;
import
org.hibernate.cfg.AnnotationConfiguration;
import
org.hibernate.classic.Session;
public class TestCase {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
try {
// Create the SessionFactory from hibernate.cfg.xml
SessionFactory sf= new
AnnotationConfiguration().configure().buildSessionFactory();
Session s=sf.openSession();
Transaction tx=s.beginTransaction();
Employee e=new Employee();
e.setEmpno(101);
e.setEname("madhav");
SalariedEmployee se=new SalariedEmployee();
se.setAnnualSal(2000);
se.setEmpno(12);
se.setEname("raghu");
s.save(se);
s.save(e);
tx.commit();
} catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
System.err.println("Initial SessionFactory creation failed." +
ex);
}
}
}
Console output:
Hibernate:
insert into employeeinfo (ename, annualSal, discriminator, empno) values (?, ?,
'se', ?)
Hibernate: insert into employeeinfo
(ename, discriminator, empno) values (?, 'e', ?)
Sqlprompt:
Sql> select * from employeeinfo;
DISCRIMINATOR
|
EMPNO
|
ENAME
|
ANNUALSAL
|
se
|
12
|
raghu
|
2000
|
e
|
101
|
madhav
|
b)
joinsubclass
Employee.java
package madhav;
import
javax.persistence.Entity;
import
javax.persistence.*;
@Entity
@Table(name="employee")
@Inheritance(strategy=InheritanceType.JOINED)
public class Employee {
@Id
private int empno;
private String ename;
public int getEmpno() {
return empno;
}
public void setEmpno(int empno) {
this.empno = empno;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
}
SalariedEmployee.java
package madhav;
import
javax.persistence.DiscriminatorValue;
import
javax.persistence.*;
@Entity
@Table(name="salariedemp")
@PrimaryKeyJoinColumn(name="empno")
public class
SalariedEmployee extends Employee {
public double annualSal;
public double getAnnualSal() {
return annualSal;
}
public void setAnnualSal(double annualSal) {
this.annualSal = annualSal;
}
}
Specifies a primary key column that is used as a foreign key to join to another table.
It is used to join the primary table of an entity subclass in the
JOINED mapping strategy to the primary
table of its superclass; it is used within a SecondaryTable
annotation to join a secondary table to a primary table; and it may be used in
a OneToOne mapping in which
the primary key of the referencing entity is used as a foreign key to the
referenced entity. If no
PrimaryKeyJoinColumn
annotation is specified for a subclass in the JOINED mapping strategy, the foreign key columns are
assumed to have the same names as the primary key columns of the primary table
of the superclass.
Ex: @PrimaryKeyJoinColumn(name="empno")
hibernate.cfg.xml
<?xml
version='1.0' encoding='UTF-8'?>
<!DOCTYPE
hibernate-configuration PUBLIC
"-//Hibernate/Hibernate
Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<!-- Generated by MyEclipse Hibernate Tools. -->
<hibernate-configuration>
<session-factory>
<property name="dialect">org.hibernate.dialect.Oracle9Dialect</property>
<property name="connection.url">jdbc:oracle:thin:@localhost:1521:XE</property>
<property name="connection.username">system</property>
<property name="connection.password">system</property>
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto"></property>
<mapping class="madhav.Employee"
/>
<mapping class="madhav.SalariedEmployee"/>
</session-factory>
</hibernate-configuration>
TestCase.java
package madhav;
import
org.hibernate.SessionFactory;
import
org.hibernate.Transaction;
import
org.hibernate.cfg.AnnotationConfiguration;
import
org.hibernate.classic.Session;
public class TestCase {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
try {
// Create the SessionFactory from hibernate.cfg.xml
SessionFactory sf= new
AnnotationConfiguration().configure().buildSessionFactory();
Session s=sf.openSession();
Transaction tx=s.beginTransaction();
Employee e=new Employee();
e.setEmpno(1);
e.setEname("madhav");
SalariedEmployee se=new SalariedEmployee();
se.setAnnualSal(2000);
se.setEmpno(107);
se.setEname("ram");
s.save(e);
tx.commit();
} catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
System.err.println("Initial SessionFactory creation failed." +
ex);
}
}
}
Console
output:
Hibernate:
insert into employee (ename, empno) values (?, ?)
Hibernate: insert into salariedemp
(annualSal, empno) values (?, ?)
Sqlprompt:
Sql>
select * from employee;
EMPNO
|
ENAME
|
0
|
ram
|
Sql> select * from salariedemp;
ANNUALSAL
|
EMPNO
|
2000
|
0
|
Problems of relationships:
a)
one –to-one
Employee.java
package madhav;
import
javax.persistence.Entity;
import
javax.persistence.*;
@Entity
@Table(name="employee")
public class Employee {
@Id
@GeneratedValue
private int empno;
private String ename;
@OneToOne(mappedBy="employee",
cascade=CascadeType.ALL)
private PersonalDetails personalDetails;
public PersonalDetails getPersonalDetails()
{
return personalDetails;
}
public void
setPersonalDetails(PersonalDetails personalDetails) {
this.personalDetails =
personalDetails;
}
public int getEmpno() {
return empno;
}
public void setEmpno(int empno) {
this.empno = empno;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
}
@OneToOne:
mappedBy
element of the OneToOne
annotation to specify the relationship field or property of the owning side. The
OneToOne annotation
may be used within an embeddable class to specify a relationship from the
embeddable class to an entity class. If the relationship is bidirectional and
the entity containing the embeddable class is on the owning side of the
relationship, the non-owning side must use the mappedBy element of the OneToOne annotation to specify the relationship field or
property of the embeddable class. The dot (".") notation syntax must
be used in the mappedBy
element to indicate the relationship attribute within the embedded attribute.
The value of each identifier used with the dot notation is the name of the
respective embedded field or property.
Ex: @OneToOne(mappedBy="employee",
cascade=CascadeType.ALL)
PersonalDetails.java
package madhav;
import
javax.persistence.*;
import
org.hibernate.annotations.GenericGenerator;
import
org.hibernate.annotations.Parameter;
@Entity
@Table(name="personaldetails")
public class
PersonalDetails{
@Id
@GeneratedValue(generator="ram")
@GenericGenerator(name="ram",
strategy="foreign", parameters=@Parameter(name="property",
value="employee"))
private int empno;
private String firstname;
private String lastname;
@OneToOne
@PrimaryKeyJoinColumn
private Employee employee;
public Employee getEmployee() {
return employee;
}
public void setEmployee(Employee employee) {
this.employee = employee;
}
public int getEmpno() {
return empno;
}
public void setEmpno(int empno) {
this.empno = empno;
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getLastname() {
return lastname;
}
public void setLastname(String lastname) {
this.lastname = lastname;
}
}
hibernate.cfg.xml
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE
hibernate-configuration PUBLIC
"-//Hibernate/Hibernate
Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<!-- Generated by MyEclipse Hibernate Tools. -->
<hibernate-configuration>
<session-factory>
<property name="dialect">org.hibernate.dialect.Oracle9Dialect</property>
<property name="connection.url">jdbc:oracle:thin:@localhost:1521:XE</property>
<property name="connection.username">system</property>
<property name="connection.password">system</property>
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto"></property>
<mapping class="madhav.Employee"
/>
<mapping class="madhav.PersonalDetails"/>
</session-factory>
</hibernate-configuration>
TestCase.java
package madhav;
import
org.hibernate.SessionFactory;
import
org.hibernate.Transaction;
import
org.hibernate.cfg.AnnotationConfiguration;
import
org.hibernate.classic.Session;
public class TestCase {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
try {
// Create the SessionFactory from hibernate.cfg.xml
SessionFactory sf= new
AnnotationConfiguration().configure().buildSessionFactory();
Session s=sf.openSession();
Transaction tx=s.beginTransaction();
PersonalDetails pd=new PersonalDetails();
pd.setFirstname("abc");
pd.setLastname("rao");
// pd.setEmpno(101);
Employee e=new Employee();
e.setEname("madhav");
// e.setEmpno(101);
e.setPersonalDetails(pd);
pd.setEmployee(e);
System.out.println("before
save");
s.save(e);
System.out.println("after save");
tx.commit();
} catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
System.err.println("Initial SessionFactory creation failed." +
ex);
}
}
}
Console output:
before save
Hibernate:
select hibernate_sequence.nextval from dual
after save
Hibernate:
insert into employee (ename, empno) values (?, ?)
Hibernate: insert into personaldetails (firstname, lastname,
empno) values (?, ?, ?)
Related Topics:
- hibernate-basic-example(xml-based)
- hibernate-inheritance-tableforclass-hierarchy(xml-based)
- hibernate-inheritance-joinsubclass-(xml-based)
- hibernate-inheritance-tableforconcreteclass(xml-based)
- hibernate-onetoone-relation(xml-based)
- hibernate-onetomany-relation(xml-based)
- hibernate-manytomany-relation(xml-based)
- hibernate-basic-example(Annotation-based)
- hibernate-inheritance-tableforclass-hierarchy(Annotation-based)
- hibernate-inberitance-joinsubclass-(Annotation-based)
- hibernate-inheritance-tableforconcreteclass(Annotation-based)
- hibernate-onetoone-relation(Annotation-based)
- hibernate-onetomany-relation(Annotation-based)
- hibernate-manytomany-relation(Annotation-based)
HIBERNATE
QUERY LANGUAGE:
TUTIORALS FROM MADHAV:
No comments:
Post a Comment