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JDBC and Relational Databases

Error while retrieving column from database

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posted 11 years ago

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I have set an attribute named USER, whose values are retrieved through a html, depending upon the user. In this jsp i need to change the password. 't1','t2','t3' are getting old password, new password & confirm password field from html.

First i am checking whether old password field and password column in database has same value.

For updating the password i am retrieving ID no also from the table. (My all tables has ID,username, and password column)

But, while retrieving ID , its showing the error, "Invalid column name". Even the index number (instead of "ID") is not working and showing the error "INVALID COLUMN NUMBER"

<%@ page import="java.sql.*" %>

<html>
<body>
<% 
try {
     Connection con=null;

PreparedStatement ps=null;

ResultSet rs=null;

String oldpass="";

long no=0;

String s=(String)session.getAttribute("user");

String t1=request.getParameter("t1");

String t2=request.getParameter("t2");

String t3=request.getParameter("t3");

if(t1.trim().length()!=0 && t2.trim().length()!=0 && t3.trim().length()!=0) {

Class.forName("oracle.jdbc.driver.OracleDriver");

con=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:oracle","scott","tiger");

ps=con.prepareStatement("select password from "+s+" where password ='"+t1+"'");

System.out.println("hi"); // for testing purpose

rs=ps.executeQuery();

System.out.println("hi1"); // for testing purpose

if(rs.next()) {

[b]no=rs.getLong("ID");[/b] [b]Showing the error[/b]

System.out.println("hi2"); // for testing purpose

System.out.println(no); // for testing purpose

if(t2.equals(t3)){

System.out.println("hi3"); // for testing purpose

response.sendRedirect("UpdatePassword.jsp");

}

else{

System.out.println("New password entered and Confirm password does not match");
}
}

else {

System.out.println("No such password exist");

}
}
else {

System.out.println("Insufficient information");

}
rs.close();

ps.close();

con.close();

session.setAttribute("NewPassword",t2);

}
catch(Exception e){

e.printStackTrace();

}

%>
</body>
</html>

kunal

Bharath Raja

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Posts: 111

posted 11 years ago

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make sure in your query..

I'm wondering that "you have separate tables for each user". If its not like that, then please check in your query, you have put the user name in the place of table name.Are you sure,"is that right"?

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Kunal Lakhani

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posted 11 years ago

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Yes, that's right. I am having different tables with "USER's " name.
Error is on Line no.41. (as checked via println statements)

kunal

Christophe Verré

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posted 11 years ago

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1. Your SELECT says : "select password". You're not getting any ID here. Did you want to do something like "select id, password..." ?
2. Are you sure that the name of the table is set in a session attribute called "user" ??

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Kunal Lakhani

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posted 11 years ago

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Yes , i am not getting any ID here. I am just checking for same password, If it is found, then i am getting the ID.
Yes, i am sure that the name of the table is set in a session attribute called "user".

kunal

Christophe Verré

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posted 11 years ago

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If it is found, then i am getting the ID.

No, you're not getting the ID. Where's the SELECT clause which retrieves the ID ?

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Bharath Raja

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posted 11 years ago

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why can't you change your select query as " select id,password from ... ". then you check your db password to user entered password..

Life is either daring something or nothing - Helen Keller

Pawan Kr Gupta

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posted 11 years ago

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Yes I agrred with Bharath ,

You should change your query first , then it will work .I think this is not an example of good code because you code could be effected by SQL injection.

Deepak Bala

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