Hibernate exception for one-to-one mapping

[Nilesh Yawale]

Hi All,

I'm using Hibernate 3.1.1 and MySQL 5.0.

Following is my first hibernate program for one-to-one mapping as follows -

Employee.java
package emp;

public class Employee {
private Long empId;

private String ename;
private String city;
private int salary;

public Employee() {
}
/****************************************************/
public Long getEmpId() {
return empId;
}

public void setEmpId(Long empId) {
this.empId = empId;
}
/****************************************************/
public String getEname() {
return ename;
}

public void setEname(String ename) {
this.ename = ename;
}

/****************************************************/

public String getCity() {
return city;
}

public void setCity(String city) {
this.city = city;
}

/****************************************************/
public int getSalary() {
return salary;
}

public void setSalary(int salary) {
this.salary = salary;
}
/****************************************************/
Machine machine=new Machine();

public Machine getMachine() {
return machine;
}

public void setMachine(Machine machine) {
this.machine = machine;
}

}

Machine.java

package emp;

import java.util.*;
public class Machine {

private String macId;
private String ipAddr;
//private String empId;

public Machine () {
System.out.println("in cons of mac");
}

Set empId= new HashSet();
/****************************************************/
public String getMacId() {
return macId;
}

public void setMacId(String macId) {
this.macId = macId;
}

/****************************************************/
public String getIpAddr() {
return ipAddr;
}

public void setIpAddr(String ipAddr) {
this.ipAddr = ipAddr;
}

}

EmployeeManager.java

package emp;
import org.hibernate.*;
import java.util.*;

import util.HibernateUtil;

public class EmployeeManager {
static Employee empObj=null;
static Machine mac = null;
/******************************************************/
public static void main(String[] args) {
EmployeeManager mgr = new EmployeeManager();

if (args[0].equals("storeMac")) {
mgr.createAndStoreMac(args[1],args[2]);
System.out.println("mac data stored...");
}
else if (args[0].equals("storeEmp")) {
String macid=mgr.createAndStoreMac(args[1],args[2]);
mgr.createAndStoreEmp(args[3],args[4],Integer.parseInt(args[5]),macid);
}
/******************************************************/
private Long createAndStoreEmp(String name, String city, int salary, String macId)
{
System.out.println("in emp...");
Session session = HibernateUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();

empObj= new Employee();

empObj.setEname(name);
empObj.setCity(city);
empObj.setSalary(salary);

Machine macObj = (Machine) session.load(Machine.class, macId);

empObj.setMachine(macObj);
session.save(empObj);
System.out.println("session id in create..........."+session);

session.getTransaction().commit();
System.out.println("in emp tx commited...");
return empObj.getEmpId();
}

/*************************************************************/
private String createAndStoreMac(String macId, String ipAddr)
{
System.out.println("in store mac...");
Session session = HibernateUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();

Machine mac= new Machine();

mac.setMacId(macId);
mac.setIpAddr(ipAddr);
session.save(mac);

session.getTransaction().commit();
System.out.println("in dept... tx done");
return mac.getMacId();
}
}

Employee.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

<class name="emp.Employee" table="myEmployee">

<id name="empId" column="EMP_ID">
<generator class="native"/>
</id>

<property name="name" column="NAME" type="string"/>
<property name="city" column="EMP_City"/>
<property name="salary"/>
<one-to-one name="macId" column= "MAC_ID" class= "emp.Machine" />

</class>

</hibernate-mapping>

Machine.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

<class name="emp.Machine" table="myMachine">

<id name="macId" column="MAC_ID"/>

<property name="ipAddr" column="IP_ADDR" type="string"/>

</class>

</hibernate-mapping>

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">

<hibernate-configuration>

<session-factory>

<!-- Database connection settings -->
<property name="connection.url">jdbc:mysql://localhost/Hibernate</property>
<property name="connection.username">root</property>
<property name="connection.password">root</property>
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>

<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>

<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>

<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>

<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">create</property>

<mapping resource="emp/Employee.hbm.xml"/>
<mapping resource="emp/Machine.hbm.xml"/>

</session-factory>

</hibernate-configuration>


When I tried to run the above code I'm getting following exception -

in store mac...
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Initial SessionFactory creation failed.org.hibernate.MappingException: Could not read mappings from resource: emp/Employee.hbm.xml
Exception in thread "main" java.lang.ExceptionInInitializerError
at util.HibernateUtil.<clinit>(HibernateUtil.java:17)
at emp.EmployeeManager.createAndStoreMac(EmployeeManager.java:110)
at emp.EmployeeManager.main(EmployeeManager.java:19)
Caused by: org.hibernate.MappingException: Could not read mappings from resource: emp/Employee.hbm.xml
at org.hibernate.cfg.Configuration.addResource(Configuration.java:484)
at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:1453)
at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:1421)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1402)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1378)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1298)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1284)
at util.HibernateUtil.<clinit>(HibernateUtil.java:13)
... 2 more
Caused by: org.hibernate.MappingException: invalid mapping
at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:424)
at org.hibernate.cfg.Configuration.addResource(Configuration.java:481)
... 9 more
Caused by: org.xml.sax.SAXParseException: Attribute "column" must be declared for element type "one-to-one".
at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
at org.apache.xerces.util.ErrorHandlerWrapper.error(Unknown Source)
at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
at org.apache.xerces.impl.dtd.XMLDTDValidator.addDTDDefaultAttrsAndValidate(Unknown Source)
at org.apache.xerces.impl.dtd.XMLDTDValidator.handleStartElement(Unknown Source)
at org.apache.xerces.impl.dtd.XMLDTDValidator.emptyElement(Unknown Source)
at org.apache.xerces.impl.XMLNSDocumentScannerImpl.scanStartElement(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at org.dom4j.io.SAXReader.read(SAXReader.java:465)
at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:421)
... 10 more


Please let me know what might be the reason behind it.

Thanks for your time.

Nilesh

[Mark Spritzler]

While you don't hvae to repost.

There is a CODE button in the 10 buttons below Add Post/Reply. Please use this button to post your code, so that all indentation is kept. When you post code/xml without indentation, we just can't read it.

Anyway, luckily we don't have to read it.

"Caused by: org.hibernate.MappingException: invalid mapping
at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:424)
at org.hibernate.cfg.Configuration.addResource(Configuration.java:481)
... 9 more
Caused by: org.xml.sax.SAXParseException: Attribute "column" must be declared for element type "one-to-one"."

so for your one-to-one mapping in the Employee.hbm.xml is missing the "column" portion of that mapping.

Mark

[Nilesh Yawale]

Hi Mark,

Thanks for the reply. But if you see my Employee.hbm.xml file there is a property metioned as -

<one-to-one name="macId" column= "MAC_ID" class= "emp.Machine" />

Please let me know your comments on the same.

Thanks for your time.

Nilesh

[Nilesh Yawale]

Any Update....please.

Thanks for your time.

Nilesh Yawale

[Mark Spritzler]

Originally posted by Nilesh Yawale:
Hi Mark,

Thanks for the reply. But if you see my Employee.hbm.xml file there is a property metioned as -

<one-to-one name="macId" column= "MAC_ID" class= "emp.Machine" />

Please let me know your comments on the same.

Thanks for your time.

Nilesh

OK, so maybe you do need to repost your code. Because if it isn't indented then I can't read it, that is why I didn't even look, to difficult to find stuff.

Thanks

Mark

[Nilesh Yawale]

Employee.java

package emp;
 
public class Employee {
private Long empId;
 
private String ename;
private String city;
private int salary;
 
public Employee() {
}
/****************************************************/
public Long getEmpId() {
return empId;
}
 
public void setEmpId(Long empId) {
this.empId = empId;
}
/****************************************************/
public String getEname() {
return ename;
}
 
public void setEname(String ename) {
this.ename = ename;
}
 
/****************************************************/
 
public String getCity() {
return city;
}
 
public void setCity(String city) {
this.city = city;
}
 
/****************************************************/
public int getSalary() {
return salary;
}
 
public void setSalary(int salary) {
this.salary = salary;
}
/****************************************************/
Machine machine=new Machine();
 
public Machine getMachine() {
return machine;
}
 
public void setMachine(Machine machine) {
this.machine = machine;
}
 
}

Machine.java

package emp;
 
import java.util.*;
public class Machine {
 
private String macId;
private String ipAddr;
//private String empId;
 
public Machine () {
System.out.println("in cons of mac");
}
 
Set empId= new HashSet();
/****************************************************/
public String getMacId() {
return macId;
}
 
public void setMacId(String macId) {
this.macId = macId;
}
 
/****************************************************/
public String getIpAddr() {
return ipAddr;
}
 
public void setIpAddr(String ipAddr) {
this.ipAddr = ipAddr;
}
 
}

EmployeeManager.java

package emp;
import org.hibernate.*;
import java.util.*;
 
import util.HibernateUtil;
 
public class EmployeeManager {
static Employee empObj=null;
static Machine mac = null;
/******************************************************/
public static void main(String[] args) {
EmployeeManager mgr = new EmployeeManager();
 
if (args[0].equals("storeMac")) {
mgr.createAndStoreMac(args[1],args[2]);
System.out.println("mac data stored...");
}
else if (args[0].equals("storeEmp")) {
String macid=mgr.createAndStoreMac(args[1],args[2]);
mgr.createAndStoreEmp(args[3],args[4],Integer.parseInt(args[5]),macid);
}
/******************************************************/
private Long createAndStoreEmp(String name, String city, int salary, String macId)
{
System.out.println("in emp...");
Session session = HibernateUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();
 
empObj= new Employee();
 
empObj.setEname(name);
empObj.setCity(city);
empObj.setSalary(salary);
 
Machine macObj = (Machine) session.load(Machine.class, macId);
 
empObj.setMachine(macObj);
session.save(empObj);
System.out.println("session id in create..........."+session);
 
session.getTransaction().commit();
System.out.println("in emp tx commited...");
return empObj.getEmpId();
}
 
/*************************************************************/
private String createAndStoreMac(String macId, String ipAddr)
{
System.out.println("in store mac...");
Session session = HibernateUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();
 
Machine mac= new Machine();
 
mac.setMacId(macId);
mac.setIpAddr(ipAddr);
session.save(mac);
 
session.getTransaction().commit();
System.out.println("in dept... tx done");
return mac.getMacId();
}
}

Employee.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 
<hibernate-mapping>
 
<class name="emp.Employee" table="myEmployee">
 
<id name="empId" column="EMP_ID">
<generator class="native"/>
</id>
 
<property name="name" column="NAME" type="string"/>
<property name="city" column="EMP_City"/>
<property name="salary"/>
<one-to-one name="macId" column= "MAC_ID" class= "emp.Machine" /> 
 
</class>
 
</hibernate-mapping>

Machine.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 
<hibernate-mapping>
 
<class name="emp.Machine" table="myMachine">
 
<id name="macId" column="MAC_ID"/>
 
<property name="ipAddr" column="IP_ADDR" type="string"/>
 
</class>
 
</hibernate-mapping>

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">
 
<hibernate-configuration>
 
<session-factory>
 
<!-- Database connection settings -->
<property name="connection.url">jdbc:mysql://localhost/Hibernate</property>
<property name="connection.username">root</property>
<property name="connection.password">root</property>
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>
 
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property> 
 
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
 
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
 
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
 
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">create</property>
 
<mapping resource="emp/Employee.hbm.xml"/>
<mapping resource="emp/Machine.hbm.xml"/>
 
</session-factory>
 
</hibernate-configuration>

[Mark Spritzler]

OK, so it looks like you are having a one-to-one unidirectional association. In the Hibernate docs, it has you use a many-to-one with a "unique" attribute

http://www.hibernate.org/hib_docs/v3/reference/en/html/associations.html#assoc-unidirectional-121

for bi-directional one to one, here are the docs, but it also has the same many-to-one usage.

http://www.hibernate.org/hib_docs/v3/reference/en/html/associations.html#assoc-bidirectional-121

Basically, just using a <one-to-one> tag on just one side isn't the correct way to map a one to one.

Good Luck

Mark