Following is a program to demonstrate working of One to Many association.
Its not working.I am also pasting the exception raised. Please Find out the fault.
I am using myeclipseIDE 8.5, with Oracle as a backend
CollegeEntity
Code:
package org.nit;
import java.io.Serializable;
public class CollegeEntity implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private Long colCode;
private String colName;
java.util.Set<StudentEntity> students;
public CollegeEntity() {}
public Long getColCode() {
return colCode;
}
public void setColCode(Long colCode) {
this.colCode = colCode;
}
public String getColName() {
return colName;
}
public void setColName(String colName) {
this.colName = colName;
}
public java.util.Set<StudentEntity> getStudents() {
return students;
}
public void setStudents(java.util.Set<StudentEntity> students) {
this.students = students;
}
}
StudentEntity
Code:
package org.nit;
import java.io.Serializable;
public class StudentEntity implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private Long id;
private String name;
public StudentEntity() {}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
hibernate.cfg.xml
Code:
<?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:orcl</property>
<property name="connection.username">hibernate</property>
<property name="connection.password">hibernate</property>
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="myeclipse.connection.profile">Hibernate</property>
<mapping resource="org/nit/college.hbm.xml"/>
</session-factory>
</hibernate-configuration>
college.hbm.xml
Code:
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated by MyEclipse Hibernate Tools. -->
<hibernate-mapping>
<class name="org.nit.CollegeEntity" table="College_stud">
<id name="colCode" type="java.lang.Long" column="College Code">
<generator class="assigned"></generator>
</id>
<property name="colName" type="java.lang.String">
<column name="College Name"></column>
</property>
<set name="students" cascade="save-update">
<key>
<column name="college_stud_fk"></column>
</key>
<one-to-many class="org.nit.StudentEntity" />
</set>
</class>
<class name="org.nit.StudentEntity" table="student_coll">
<id name="id" type="java.lang.Long" column="id">
<generator class="assigned"></generator>
</id>
<property name="name" type="java.lang.String" column="name"></property>
</class>
</hibernate-mapping>
TestClient
Code:
package org.nit;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
public class TestClient {
/**
* @param args
*/
public static void main(String[] args) {
Configuration config = new Configuration();
config.configure();
new SchemaExport(config).create(true, true);
SessionFactory factory = config.buildSessionFactory();
Session session = factory.openSession();
Transaction trans = session.beginTransaction();
System.out.println("Success1");
StudentEntity se1 = new StudentEntity();
se1.setId(1L);
se1.setName("Kunal");
StudentEntity se2 = new StudentEntity();
se2.setId(2L);
se2.setName("Karan");
System.out.println("Success2");
java.util.Set<StudentEntity> students=new java.util.HashSet<StudentEntity>();
students.add(se1);
students.add(se2);
CollegeEntity ce = new CollegeEntity();
ce.setColCode(1L);
ce.setColName("St.Xaviers");
ce.setStudents(students);
System.out.println("Success3");
session.saveOrUpdate(ce);
/*session.save(se1);
session.save(se2);*/
trans.commit();
session.close();
factory.close();
}
}
Output in the console
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
drop table College_stud cascade constraints
drop table student_coll cascade constraints
create table College_stud (College Code number(19,0) not null, College Name varchar2(255 char), primary key (College Code))
create table student_coll (id number(19,0) not null, name varchar2(255 char), college_stud_fk number(19,0), primary key (id))
alter table student_coll add constraint FKFEDA1270A10B24A7 foreign key (college_stud_fk) references College_stud
Success1
Success2
Success3
Exception in thread "main" org.hibernate.exception.SQLGrammarException: could not retrieve snapshot: [org.nit.CollegeEntity#1]
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:90)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
at org.hibernate.persister.entity.AbstractEntityPersister.getDatabaseSnapshot(AbstractEntityPersister.java:1065)
at org.hibernate.engine.StatefulPersistenceContext.getDatabaseSnapshot(StatefulPersistenceContext.java:269)
at org.hibernate.engine.ForeignKeys.isTransient(ForeignKeys.java:212)
at org.hibernate.event.def.AbstractSaveEventListener.getEntityState(AbstractSaveEventListener.java:535)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:103)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93)
at org.hibernate.impl.SessionImpl.fireSaveOrUpdate(SessionImpl.java:535)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:527)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:523)
at org.nit.TestClient.main(TestClient.java:50)
Caused by: java.sql.SQLException: ORA-00923: FROM keyword not found where expected
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:331)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:288)
at oracle.jdbc.driver.T4C8Oall.receive(T4C8Oall.java:743)
at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:213)
at oracle.jdbc.driver.T4CPreparedStatement.executeForDescribe(T4CPreparedStatement.java:796)
at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1031)
at oracle.jdbc.driver.T4CPreparedStatement.executeMaybeDescribe(T4CPreparedStatement.java:836)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1124)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3285)
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3329)
at org.hibernate.persister.entity.AbstractEntityPersister.getDatabaseSnapshot(AbstractEntityPersister.java:1038)
... 9 more
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