Deleting Record in a Web Application.

[Devi Ramadass]

Hi,

I want to delete the paricular record in hibernate web application. Can anyone knows please tell me.

Regards
Devi Ramadass

[Devi Ramadass]

Hi,

Any one knows please help me.

Regards
Devi Ramadass

[Scott Selikoff]

Have you tried the Hibernate APIs? For pre-Hibernate3, you can use Session.delete(), and for current versions its recommended you should use HQL's createQuery() with delete in the query.

[Devi Ramadass]

Hi,

In my code i am not getting idea to delete the particular record from the list.
1.How i get the id in the DAO Class for deleting?
2.I sent the through param tag.



In my table structure is

CREATE TABLE `employee` (
  `EMPID` int(3) NOT NULL auto_increment,
  `FirstName` varchar(25) collate latin1_general_ci NOT NULL,
  `LastName` varchar(25) collate latin1_general_ci NOT NULL,
  `Designation` varchar(25) collate latin1_general_ci NOT NULL,
  PRIMARY KEY  (`EMPID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci AUTO_INCREMENT=98 ;

Employee.class

public class Employee
{
private String firstname;
private String lastname;
private String designation;

private long id;
public Employee() 
{
    }
public Employee(String firstname,String lastname,String designation)
{
this.firstname = firstname;
this.lastname = lastname;
this.designation = designation;
}
        //getter and setter for all properties.

EmployeeDBConn.java

public class EmployeeDBConn
{
public List<Employee> employees;
//private Employee employee=new Employee();
Map map;
SessionFactory sessionFactory=null;
Query query;
Session session=null;
private EmployeeDBConn employeedb;

public EmployeeDBConn() 
{
URL url = EmployeeDBConn.class.getResource("hibernate.cfg.xml");
sessionFactory = new Configuration().configure(url).buildSessionFactory();
      map= ActionContext.getContext().getSession();
session =sessionFactory.openSession();

//Using from Clause
String SQL_QUERY ="from Employee employee ";
query = session.createQuery(SQL_QUERY);
employees = query.list();
}

public EmployeeDBConn getEmployeedb()
{
return employeedb;
}

public void removeEmployee(int id)
{
 
}


public List<Employee> getemployees()
{
return employees;
}
public void setemployees(List<Employee> employees)
{
this.employees = employees;
}

 
}

EmployeeList.java

 
public class EmployeeList extends ActionSupport
{
SessionFactory sessionFactory=null;
Query query;
Session session=null;
private static final long SerialVersionUID = 1L;
    private long id;
    public EmployeeDBConn employeedao = new EmployeeDBConn();
    private Employee employee;
public static List employees;

public String getAllEmployees()
{
 employeedao.getEmployeedb();
    employees = employeedao.getemployees();
    return SUCCESS;
    }
public String removeEmployee()
    {
//Here i want to delete the record how can i get the id, and delete.
        System.out.println("Delete Method Invoked"+id);
       return SUCCESS;
    }

public Employee getEmployee()
{
return employee;
}
public void setEmployee(Employee employee)
{
this.employee = employee;
}
public List getemployees()
{
return employees;
}
public void setemployees(List employees)
{
this.employees = employees;
}

 
} 

<hibernate-mapping>
  <class name="pages.Employee" table="employee">
   <id name="id" type="long" column="EMPID" >
   <generator class="assigned"/>
  </id>
  <property column="FirstName" name="firstName" type ="java.lang.String" />
  <property column="LastName" name="lastName" type ="java.lang.String"/>
  <property column="Designation" name="designation" type ="java.lang.String"/>
   
   </class>
 </hibernate-mapping>

Jsp Code is

 
 <s:iterator value="employees" id="employee">
       <tr class="nowrap">  
         <td class="nowrap"> <s:property value="firstName"/></td>
          <td class="nowrap"> <s:property value="lastName"/></td>
         <td class="nowrap"> <s:property value="designation"/> </td>
         <td class="nowrap"><s:property value="id"/> 
         <s:url id="delete" action="delete">
         <s  :p  aram name="id" value="id"/>
 </s:url> 
 <s:a href="%{delete}">Delete</s:a>
 
 <s:url id="edit" action="edit">
         <s:param name="id" value="id"/>
 </s:url> 
 <s:a href="%{edit}">Edit</s:a>
   </s:iterator>

Please suggest me.

Regards
Devi Ramadass

[ Edited to use code tags - Paul Sturrock ]
[ September 29, 2008: Message edited by: Paul Sturrock ]

[Devi Ramadass]

Any inputs...........

Regards
Devi Ramadass

[Paul Sturrock]

1.How i get the id in the DAO Class for deleting?

The id is a property of Employee. The objects returned from your query will have this value populated.

[Devi Ramadass]

Hi,

This is the query i am using

String hql =" from Employee employee where EMPID=?"; 
        Query qry = session.createQuery(hql);
qry.setLong(0,id);

From this query how can i get the id and set it to Employee object for delete.

Regards
Devi Ramadass

[Devi Ramadass]

Any Suggestion.........

[Paul Sturrock]

From this query how can i get the id and set it to Employee object for delete.

You don't need to set it in the Employee object, Hibernate does that for you. The result of your query is a List of Employee objects. Their ID property will be populated already.

[Vijay Gadde]

Hi, I was successfully implimented this Delete in my Hibernate application.

Here is the code YOU need to try, don't worry about ID setting and all..!

        int id=123;
        //Query to select employee with EMPID=?
        String hql =" from Employee employee where EMPID=:EMPID"; 
        //Setting 
        Query qry = session.createQuery(hql).setParameter("EMPID",id);
        //By this line u got required employee object Now go ahead and      
        //delete..!  
        //Assume there is only one record selected out of ur query - I  
        //don't know better than this.
        employee = (Employee)qry.list().get(0);
        //delete the Employee object and commit the transaction.
        session.delete(employee);
        transaction.commit();
        

Hope this helps wish YOU good luck VIJAY

[Devi Ramadass]

Hi,

Thank you for your reply It's working fine.But Could you suggest how to get the id of the particular record which is selected from the list instead of assigning it statically (int id=123 .

Regards
Devi Ramadass.
[ October 09, 2008: Message edited by: Devi Ramadass ]

[Devi Ramadass]

Any Inputs Please....

Regards
Devi Ramadass

[Vijay Gadde]

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**First thing I took this ID as an example.
 
Here is example sudo code for you, please try think this way.
 
To delete any Persisted object from Database using Hibernate, first we need to get the Object instance, I mean first you need to run a select query by passing where condition. When u run the select query like below
 
//user Id - u will pass this value to this query at run time.
String query = "from User as user where user.userID=:userId"
 
List list = session.createQuery(query).setParameter("userId",userId);
 
when you execute above query u will get a list of rows, and assume that UserID is primary key on this User table so u r going to get only one row.
User = (User)list.get(0);
session.delete(User);
transaction.commit();

Hope this helps.
Thanks,VIJAY

[Ramesh Srinivasan]

Originally posted by Devi Ramadass:
Any Inputs Please....

Regards
Devi Ramadass

Hi,

If you ask Hibernate to employee.getId() it will give you the ObjectId which was assigned.

I have seen your code there was long id has mentioned your EMPLOYEE class it will return Id of your object.

~Ramesh.

[Devi Ramadass]

Hai,

If you ask Hibernate to employee.getId() it will give you the ObjectId which was assigned.

I have seen your code there was long id has mentioned your EMPLOYEE class it will return Id of your object.

~Ramesh..

------------------
If i print the return id through this statement System.out.println("Employee Id="+employee.getId()) i am getting the value zero. Instead of that i want to get the selected employee id.Please suggest.

Thank you for all Inputs.
Regards
Devi Ramadass

[Devi Ramadass]

Hi,

//user Id - you will pass this value to this query at run time.String query
String query = "from User as user where user.userID=:userId"

I passing the employee id but i am getting the value zero. Instead of that i want to get the selected employee id.Please suggest.
Regards
Devi Ramadass.
[ October 11, 2008: Message edited by: Devi Ramadass ]

[Vijay Gadde]

Rather asking same question repeatedly... please google and try to understnad some basic concepts arround Hibernate...javascript:%20x()
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