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Changing column name

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In this section, you will learn how to change the column name.

Changing column name

     

We make a table for storing some type of data. Table keeps the data in the form of rows and columns. Column indicates the field while row indicate the data of the field. Now consider a scenario where we have a table and it consists some data and a situation arises where there is a need to change the name of the column. As this is not the work of the programmer to change the name of the field, but as a programmer we should be aware how we can change the name of the column. 

The name of the column of the column will be changed by using the simple query. But before going into it we should see what are the initial steps to get the desired results. First of all make a database connection with your program. When the connection has been established pass a query for changing the column name in the preparedStatement(). This will return the PreparedStatement object.

The code of the program is given below:

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.sql.*;

public class ServletChangingColumnName extends HttpServlet{
  public void doGet(HttpServletRequest request, HttpServletResponse
    response
)throws ServletException, IOException{
  response.setContentType("text/html");
  PrintWriter pw = response.getWriter();
  String connectionURL = "jdbc:mysql://localhost/zulfiqar";
  Connection connection;
  try{
  Class.forName("org.gjt.mm.mysql.Driver");
  connection = DriverManager.getConnection(connectionURL,
    
"root","admin");
  PreparedStatement pst = connection.prepareStatement
  (
"alter table emp_details change firstname Name varchar(10)");
  int i = pst.executeUpdate();
  pw.println("The name of the column has been changed");
  }
  catch(Exception e){
  pw.println("The exception is " + e);
  }
  }
}

web.xml file for this program:

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
 PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>
 <servlet>
 <servlet-name>Zulfiqar</servlet-name>
 <servlet-class>ServletChangingColumnName</servlet-class>
 </servlet>
 <servlet-mapping>
 <servlet-name>Zulfiqar</servlet-name>
 <url-pattern>/ServletChangingColumnName</url-pattern>
 </servlet-mapping>
</web-app>

The table in the database before changing of column name:

mysql> select * from emp_details;
+--------+----------+---------+-----------+----------+-------+-----------
| userId | Name | surname | address1 | address2 | town | country | zipcode
+--------+----------+---------+-----------+----------+-------+-----------
| 73979 | zulfiqar | Ahmed | Moradabad | Delhi | Okhla | India | 110025
+--------+----------+---------+-----------+----------+-------+-----------
1 row in set (0.00 sec)

The output of the program is given below:

The table in the database after changing the column name:

mysql> select * from emp_details;
+--------+-----------+---------+-----------+----------+-------+-----------
| userId | firstname | surname | address1 | address2 | town | country | zipcode
+--------+-----------+---------+-----------+----------+-------+-----------
| 73979 | zulfiqar | Ahmed | Moradabad | Delhi | Okhla | India | 110025
+--------+-----------+---------+-----------+----------+-------+-----------
1 row in set (0.03 sec)

Download this program

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Posted on: July 19, 2007

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