why this program is not executing when it goes in to the do while loop second time and why it is giving the exception "Exception java.sql.SQLException: [MySQL][ODBC 5.1 Driver][mysqld-5.0.51a-community-nt]No database selected"

```
//import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;
import java.util.Vector;

public class DataBase {

    public void LoadDriver() {

        // Load the JDBC-ODBC bridge driver
        try {
            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
        } catch (ClassNotFoundException ee) {
            ee.printStackTrace();
        }
    }

    // 2.open a data source name by means of the jdbcodbcdriver.

    static void connect() throws SQLException {

        // Connect to the database
        Connection con = DriverManager.getConnection("jdbc:odbc:MySQL", "root", "admin");
        Statement stmt = con.createStatement();
        // Shut off autocommit
        con.setAutoCommit(false);

        System.out.println("1.Insert 2.Delete 3.Update 4.Select");
        Scanner s = new Scanner(System.in);
        int x;
        x = s.nextInt();

        String query; // SQL select string
        ResultSet rs; // SQL query results
        boolean more; // "more rows found" switch
        String v1, v2; // Temporary storage results

        Vector<Object> results = new Vector<Object>(10);

        if (x == 1) {

            try {
                stmt.executeUpdate("INSERT INTO employee( emp_id,emp_name ) VALUES ( '122','shiva' ) ");
            } catch(Exception e){System.out.println("Exception " +e);e.printStackTrace();}
        }

        if (x == 2) {

            try {
                stmt.executeUpdate("DELETE from employee where emp_id='102' ");
            }catch(Exception e){System.out.println("Exception "+e);e.printStackTrace();} 
        }

        if (x == 3) {

            try {
                stmt
                        .executeUpdate("UPDATE employee SET emp_name = 'madavan' where emp_id='20'; ");
            } catch(Exception e){System.out.println("Exception "+e);e.printStackTrace();} 
        }

        query = "SELECT * FROM employee ";
        try {
            rs = stmt.executeQuery(query);
            // Check to see if any rows were read
            more = rs.next();
            if (!more) {

                System.out.println("No rows found.");
                return;
            }

            // Loop through the rows retrieved from the query
            while (more) {

                v1 = "ID: " + rs.getInt("emp_id");
                v2 = "Name: " + rs.getString("emp_name");

                System.out.println(v1);
                System.out.println(v2);
                System.out.println("");

                results.addElement(v1 + "\n" + v2 + "\n");

                more = rs.next();
            }
            rs.close();

        } catch (SQLException e) {
            System.out.println("" + results.size() + "results where found.");
        } 
        finally{stmt.close();}
    }

    public static void main(String[] args) throws SQLException {
        String str = "y";
        do {
            DataBase s = new DataBase();
            s.LoadDriver();
            DataBase.connect();
        Scanner sc = new Scanner(System.in);
        System.out.println("DO u Want to PROCEED TO QUERY : ");
        str = sc.next();
        } while (str !="n");
    }

}

```
['https://Stackoverflow.com/questions/584870', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/-1/']
Unless you have to use the jdbc/odbc driver I would use the straight mysql jdbc driver. You can download it free from mysql.

then 

```
public void LoadDriver() {

        // Load the JDBC-ODBC bridge driver
        try {
                Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException ee) {
                ee.printStackTrace();
        }
}

static void connect() throws SQLException {

        // Connect to the database
        Connection con = DriverManager.getConnection("jdbc:mysql:host/databasename", "root", "admin");
        Statement stmt = con.createStatement();
...

```
Is the ODBC source actually set up to select a database? eg. can you access the database through another ODBC client tool?

If you need to select a database explicitly in the JDBC string you can do that using the ‘database’ parameter.

But having the database chosen in the ODBC setup would be more usual. And indeed, as Clint mentioned, using the normal MySQL JDBC driver instead of ODBC would be more usual still.

> 
> while (str !="n")
> 
> 
> 

[That's not how you compare strings in Java.](http://www.owasp.org/index.php/Java_gotchas#Equality)