问Java:jdbc不更新数据

EN

package model;
import java.sql.*;
public class Datahandler {

    public ResultSet databaseResult(Connection c,String query) throws SQLException{
        Statement stmt=c.createStatement();
        ResultSet rs=stmt.executeQuery(query);
        return rs;
    }

    public void databaseDelete(Connection c,String query) throws SQLException{
        Statement stmt=c.createStatement();
        stmt.executeUpdate(query);
    }

    public  int databaseInsert(Connection c,Contactdb pb) throws SQLException{
        int rowsaffected=0;
        try{
            String query="INSERT INTO contactDb (first_name,last_name,phone_number,company_name,state,city,street,building_no) VALUES (?,?,?,?,?,?,?,?)";
            PreparedStatement statement = c.prepareStatement(query); 
            statement.setString(1, pb.get_firstname());
            statement.setString(2,pb.get_lastname());
            statement.setString(3, pb.get_phonenumber());
            statement.setString(4, pb.get_companyname());
            statement.setString(5, pb.get_state());
            statement.setString(6, pb.get_city());
            statement.setString(7, pb.get_street());
            statement.setInt(8,pb.get_buildingno());
            statement.execute();
        } catch(SQLException e){
            e.printStackTrace();
        } finally {
            c.close();
        }
        return rowsaffected;
    }

    public int databaseUpdate(Connection c,Contactdb pb) throws SQLException{
        int a=0;
        try{
            String query="UPDATE contactDb SET  first_name=?,last_name=?,phone_number=?,company_name=?,state=?,city=?,street=?,building_no=? WHERE sn=?";
            a=69;
            PreparedStatement statement = c.prepareStatement(query); 
            statement.setString(1, pb.get_firstname());
            statement.setString(2,pb.get_lastname());
            statement.setString(3, pb.get_phonenumber());
            statement.setString(4, pb.get_companyname());
            statement.setString(5, pb.get_state());
            statement.setString(6, pb.get_city());
            statement.setString(7, pb.get_street());
            statement.setInt(8,pb.get_buildingno()); 
            statement.setInt(9,pb.get_sn());
        } catch(SQLException e){
            e.printStackTrace();
        } finally{
            c.close();
        }
        return a;
    }
}