Deleting dynamic records in database using Servlets and JDBC

[cygsoft]

Hi,

I have got the codings for inserting and displaying the records in the database. But i couldn't able to delete a specific row, which is created dynamically.

i.e, if i give any one of the field value in a text box, then using the request.getParameter() method i have to delete the entire record with the value given in the textbox.

I need the jdbc codings....... for that........

i have tried the following codings but it does not work.

Statement st = con.createStatement("DELETE FROM email WHERE email="+'"'+request.getParameter("email1")+'"');
ResultSet rs=st.executeQuery();


The solution can also be in MVC pattern.


It would be so helpful, if u provide me the solution.

[r035198x]

Hi,

I have got the codings for inserting and displaying the records in the database. But i couldn't able to delete a specific row, which is created dynamically.

i.e, if i give any one of the field value in a text box, then using the request.getParameter() method i have to delete the entire record with the value given in the textbox.

I need the jdbc codings....... for that........

i have tried the following codings but it does not work.

Statement st = con.createStatement("DELETE FROM email WHERE email="+'"'+request.getParameter("email1")+'"');
ResultSet rs=st.executeQuery();


The solution can also be in MVC pattern.


It would be so helpful, if u provide me the solution.

What happens when you run the program? Do you get an exception?

[cygsoft]

What happens when you run the program? Do you get an exception?

When it is executed a compile time error is generated.
The problem is with the "request.getParameter()" and returning the ResultSet.

[r035198x]

When it is executed a compile time error is generated.
The problem is with the "request.getParameter()" and returning the ResultSet.

Post the errors that you got then

[koneru9999]

i think u have to use executeUpdate() rather than ecexuteQuery().
and also one more change

Statement st = con.createStatement();
String sql = "DELETE FROM email WHERE email="+"'+request.getParameter("email1")'"";
ResultSet rs=st.executeUpdate(sql);

i think it will work for u...
check once.

[r035198x]

i think u have to use executeUpdate() rather than ecexuteQuery().
and also one more change

Statement st = con.createStatement();
String sql = "DELETE FROM email WHERE email="+"'+request.getParameter("email1")'"";
ResultSet rs=st.executeUpdate(sql);

i think it will work for u...
check once.

Erm, executeUpdate returns an int

[koneru9999]

ooh..sorry yar...

then is there any need to get record into resultset????

[cygsoft]

One small change.....
In case of MVC architecture, is it possible to delete the individual records by calling bean file.

It works well for inserting and displaying the records.........
I just give here the servlet and bean file for inserting and displaying.
Can anyone modify it and make it use for deleting the records...........

Servlet file

 import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.sql.*;
 
public class dbServlet extends HttpServlet
{
public void doGet(HttpServletRequest req,HttpServletResponse res)throws ServletException,IOException
{
res.setContentType("text/html");
PrintWriter pw=res.getWriter();
try
{
dbBean bean=new dbBean();
bean.connect();
RequestDispatcher rd=null;
 
if((req.getParameter("action")).equals("insert"))
{
bean.setName(req.getParameter("name1"));
bean.setAge(Integer.parseInt(req.getParameter("age1")));
bean.insert();
rd=req.getRequestDispatcher("/insert.jsp");
rd.forward(req,res);
}
 
 
if((req.getParameter("action")).equals("display"))
{
 
 
bean.getName();
bean.getAge();
ResultSet rs=bean.display();
req.setAttribute("RSObject",rs);
rd=req.getRequestDispatcher("/display.jsp");
rd.forward(req,res);
 
}
}
catch(Exception e)
{
System.out.println(e);
}
}
}

Bean file

 import java.sql.*;
 
public class dbBean 
{
 
Connection con=null;
String name;
int age;
 
public void connect()
{
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); 
con = DriverManager.getConnection("jdbc:odbc:data");
}
catch(Exception e)
{
System.out.println(e);
}
}
 
public void setName(String name)
{
 
this.name=name;
}
 
public void setAge(int age)
{
 
this.age=age;
}
 
public void insert()
{
try
{
PreparedStatement stmt = con.prepareStatement("insert into login(name,age) VALUES (?,?)");
 
stmt.setString(1,name);
stmt.setInt(2,age);
stmt.executeUpdate();
}
catch(Exception e)
{
System.out.println(e);
}
}
 
public String getName()
{
return name;
}
 
public int getAge()
{
return age;
}
 
 
public ResultSet display()
{
ResultSet rs=null;
try
{
Statement stmt = con.createStatement();
 rs=stmt.executeQuery("select * from login");
}
catch(Exception e)
{
System.out.println(e);
}
return rs;
}
 
 

}

and the Result set is returned to jsp where JSP displays the records.............

Pls can anyone modify it and make it use for deleting the records......

[cygsoft]

Yes,
the final resultset has to be returned after deletion and displayed.