Create dbBroker Class which contain database connection string (dbBroker.cs).
using System;
using MVCLibDefination;
using MVCLibFramwork; 
namespace MVCLibBusinessObjects
{
      /// <summary>
      /// Summary description for dbBroker.
      /// </summary>
      public class dbBroker 
      {
            public String getConnectionString()
            {
                  String strConn="";
                  strConn="server=pol005;user Id=haritha;password=haritha;database=haritha;Pooling=yes;Min Pool Size=0;Max Pool Size=25;Connect Timeout=90";
                  return strConn;
            }
      }
}
4. Create CityMaster Entity class (file name CityMaster.cs).
using System;
using MVCLibBusinessObjects;
using MVCLibDefination;
using MVCLibFramwork;
namespace MVCLibBusinessObjects
{
      /// <summary>
      /// Summary description for CityMaster.
      /// </summary>
      public class CityMaster : BusinessEntity
      {
            private int vCityCode=0;
            private String vCityName="";
            public int CityCode
            {
                  get 
                  {
                        return vCityCode;
                  }
                  set
                  {
                        vCityCode=value;
                  }
            }
            public String CityName
            {
                  get
                  {
                        return vCityName;
                  }
                  set
                  {
                        vCityName=value;
                  }
            }
      }
}
5. Create CityMaster Business Class (CityMasterBO.cs).
Note: We are making use of "Microsoft.ApplicationBlocks.Data" namespace in below class
using System;
using MVCLibDefination;
using MVCLibFramwork;
using Microsoft.ApplicationBlocks.Data;
using System.Data;
using System.Data.SqlClient;
using System.Collections;
using System.Web;
using System.Web.UI;
namespace MVCLibBusinessObjects
{
      /// <summary>
      /// Summary description for CityMasterBO.
      /// </summary>
      public class CityMasterBO : BusinessLogic, IbusinessLogic
      {
            String strConn=""; 
            String strQuery="";
            CityMaster varCityMaster=new CityMaster();
            ArrayList IBusiness.GetData(object vCityMaster)
            {
            ArrayList arylist=new ArrayList();
                  varCityMaster=(CityMaster) vCityMaster;
                  dbBroker dbb=new dbBroker();
                  strConn= dbb.getConnectionString(); //dbb.getConnectionStr.ToString();
                  try
                  {
                        if (varCityMaster.CityCode==0)
                        {
                              strQuery="select citycode,cityname from citymaster";
                        }
                        else
                        {
                              strQuery="select citycode,cityname from citymaster where
citycode=" + varCityMaster.CityCode ;
                        }
                        SqlDataReader rdrSql;
                        rdrSql=SqlHelper.ExecuteReader(strConn,CommandType.Text,strQuery);
                        while (rdrSql.Read())
                        {
                              int intCityCode=rdrSql.GetInt32(0);
                              String strCityName=rdrSql.GetString(1);
                              CityMaster cm=new CityMaster();
                              cm.CityCode=intCityCode;
                              cm.CityName=strCityName;
                              arylist.Add(cm);
                        }
                        rdrSql.Close();
                  }
                  catch(Exception exp)
                  {
                        HttpContext.Current.Response.Write("Error : " + exp.ToString());
                  }
                  return arylist;
            }
            bool IBusiness.DataExists(object vCityMaster)
            {
                  bool blnflag=false;
                  try
                  {
                        dbBroker dbb=new dbBroker();
                        strConn= dbb.getConnectionString(); //dbb.getConnectionStr.ToString();
                        //HttpContext.Current.Response.Write("Conn : " + strConn);
                      
 			varCityMaster=(CityMaster) vCityMaster; 
                         strQuery="select count(*) from CityMaster where cityname='" + varCityMaster.CityName.ToUpper().Trim() + "'";
                        
                        int intCnt=0;
                        //HttpContext.Current.Response.Write("Query : " + strQuery);
                        
                        intCnt= (int) SqlHelper.ExecuteScalar(strConn,CommandType.Text,strQuery);
                        if (intCnt>0)
                        {
                              blnflag=true;
                        }
                  }
                  catch(Exception exp)
                  {
                        HttpContext.Current.Response.Write("Error : " + exp.ToString());
                  }
                  return blnflag;
            }
            bool IBusiness.Insert(object vCityMaster)
            {
                  bool blnflag=false;
                  dbBroker dbb=new dbBroker();
                  strConn= dbb.getConnectionString(); //dbb.getConnectionStr.ToString();
                  SqlConnection cnnCon=new SqlConnection();
                  cnnCon.ConnectionString=strConn;
                  if (cnnCon.State==ConnectionState.Closed) 
                  { 
                        cnnCon.Open();
                  }
                  SqlTransaction sqlTrans=cnnCon.BeginTransaction();
                  try
                  {
                        varCityMaster=(CityMaster) vCityMaster;
                        strQuery="insert into CityMaster(cityname) values('" + varCityMaster.CityName.ToUpper().ToString() + "')";
                        SqlHelper.ExecuteNonQuery(sqlTrans,CommandType.Text,strQuery);
                        sqlTrans.Commit();
                        blnflag=true;
                  }
                  catch(Exception exp)
                  {
                        HttpContext.Current.Response.Write("Error : " + exp.ToString());
                        sqlTrans.Rollback();
                  }
                  return blnflag;
            }
            bool IBusiness.Update(object vCityMaster)
            {
                  bool blnflag=false;
                  dbBroker dbb=new dbBroker();
                  strConn= dbb.getConnectionString(); //dbb.getConnectionStr.ToString();
                  SqlConnection cnnCon=new SqlConnection();
                  cnnCon.ConnectionString=strConn;
                  if (cnnCon.State==ConnectionState.Closed) 
                  { 
                        cnnCon.Open();
                  }
                  SqlTransaction sqlTrans=cnnCon.BeginTransaction();
                  try
                  {
                        varCityMaster=(CityMaster) vCityMaster;
                        strQuery="update CityMaster set cityname='"+ varCityMaster.CityName.ToUpper().ToString() + "' where citycode="+ varCityMaster.CityCode;
                        SqlHelper.ExecuteNonQuery(sqlTrans,CommandType.Text,strQuery);
                        sqlTrans.Commit();
                        blnflag=true;
                  }
                  catch(Exception exp)
                  {
                        HttpContext.Current.Response.Write("Error : " + exp.ToString());
                        sqlTrans.Rollback();
                  }
                  return blnflag;
            }
            bool IBusiness.Delete(object vCityMaster)
            {
                  bool blnflag=false;
                  dbBroker dbb=new dbBroker();
                  strConn= dbb.getConnectionString(); //dbb.getConnectionStr.ToString();
                  SqlConnection cnnCon=new SqlConnection();
                  cnnCon.ConnectionString=strConn;
                  if (cnnCon.State==ConnectionState.Closed) 
                  { 
                        cnnCon.Open();
                  }
                  SqlTransaction sqlTrans=cnnCon.BeginTransaction();
                  try
                  {
                        varCityMaster=(CityMaster) vCityMaster;
                        strQuery="delete from CityMaster where citycode="+ varCityMaster.CityCode;
                        SqlHelper.ExecuteNonQuery(sqlTrans,CommandType.Text,strQuery);
                        sqlTrans.Commit();
                        blnflag=true;
                  }
                  catch(Exception exp)
                  {
                        HttpContext.Current.Response.Write("Error : " + exp.ToString());
                        sqlTrans.Rollback();
                  }
                  return blnflag; 
            }
      }
}