ASP.NET

string update = " update ds1 set name='asd' where Code='" + s.ToString() + "'";

s=(string)command.executescaler();

bigint

string Code = "select Code from ds1 " ;
int s;
using (SqlCommand command = new SqlCommand(Code, conn))
{
  s = (int)command.ExecuteScalar();
}

string update = " update ds1 set name='asd' where Code='" + s + "'";

public int GetData()
  {
     int Code;

     String strCon = "blablablablablablabla";

     SqlConnection con = new SqlConnection(strCon);

     SqlCommand cmdselect = new SqlCommand();

     cmdselect.CommandText = "select Code from ds1";

     cmdselect.Connection = con;

     try
     {
         con.Open();

         Code = (int)cmdselect.ExecuteNonQuery();

     }
      catch(SqlException)
     {
          throw;
     }
      finally
     {
         con.Close();
     }

     return Code;

  }