Selenium Database Testing

What is testing? How to perform database  testing using Selenium WebDriver

package DatabaseTest;

import java.sql.*;

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;

public class SeleniumDatabaseTesting {

public static void main(String[] args) {

//Testdata
String email = "vivek@rediffmail.com";
String zipcode = "222222";
String firstname= "Lucky";
String lastname = "Singh";


/* //Input testdata using Selenium
WebDriver driver = new FirefoxDriver();
driver.get("http://mailing.dollartree.com/user/signup.jsp");
driver.findElement(By.xpath("//*[@id='emailAddress']")).sendKeys(email);
driver.findElement(By.xpath("//*[@id='zipCode']")).sendKeys(zipcode);
driver.findElement(By.xpath("//*[@id='firstName']")).sendKeys(firstname);
driver.findElement(By.xpath("//*[@id='lastName']")).sendKeys(lastname);
driver.findElement(By.xpath("//*[@id='subscribeForm']/div[2]/input[4]")).click();
        driver.findElement(By.xpath("//*[@id='subscribeForm']/div[3]/input[2]")).click();


*/


//Connecting to database
Connection conn = null;

String url = "jdbc:mysql://localhost:3306/";
String databaseName = "mydatabase";
String username = "root";
String password = "root";

try{
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(url+databaseName, username, password);

//String sqlQuerry = "Select * from signupdetails";
String sqlQuerry = "Select * from signupdetails ORDER BY signupid DESC LIMIT 1";
Statement statement = conn.createStatement();
ResultSet result = statement.executeQuery(sqlQuerry);


result.next();
System.out.println(result.getString("emailaddress"));
System.out.println(result.getString("zipcode"));
System.out.println(result.getString("firstname"));
System.out.println(result.getString("lastname"));

//Database Testing
if(!result.getString("emailaddress").equals(email))
System.out.println("email ID is stored wrong");
if(!result.getString("zipcode").equals(zipcode))
System.out.println("zipcode is stored wrong");
if(!result.getString("firstname").equals(firstname))
System.out.println("firstname is stored wrong");
if(!result.getString("lastname").equals(lastname))
System.out.println("lastname is stored wrong");

}
catch(Exception e){
System.out.println(e);
}
finally{
if(conn!=null){
conn=null;
}

}



}


}