function get_records($table, $where=NULL)
    {
        if(!empty($where))
        {
            $this->db->where($where);
        }
        $query=$this->db->get($table);
        if($query->num_rows>0)
        {
            return $query->result();
        }
        else
        {
            return array();
        }

function get_record($table, $where=NULL)
    {
        if(!empty($where))
        {
            $this->db->where($where);
        }
        $query=$this->db->get($table);
        if($query->num_rows>0)
        {
            return $query->row();
        }
        else
        {
            return 0;
        }
    }

function update($table ,$where=NULL ,$data)
{
    if(!empty($where))
    {
        $this->db->where($where);
    }
    $query=$this->db->update($table,$data);
    if($query)
    {
        return $this->db->affected_rows();
    }

}

function delete($table , $where=NULL)
    {
        if(!empty($where))
        {
            $this->db->where($where);
        }
        if($this->db->delete($table))
        {
            return $this->db->affected_rows();
        }
    }