How to fix this issue with advanced search codeigniter - codeigniter

Question

I want to build advanced search script but I have this error with search_all function in the model
A PHP Error was encountered
Severity: 4096
Message: Object of class CI_DB_mysql_result could not be converted to string
Filename: models/search_model.php
Line Number: 129
i have four fildes
1- input text to write the book name
2- select box for the author
3- select box for the publisher
3-select box for the section
the model is
class search_model extends CI_Model
{
function __construct()
{
parent::__construct();
}
/* This function get all search in database sort by order asc.*/
function get_new_one($id)
{
$this->db->where('ne_id',$id);
$result=$this->db->get('d_search');
return $result->row();
}
//////////////frontend//////////////////////////////////////////////////////////
function show_new($id)
{
$result=$this->db->query("SELECT * , COUNT( d_comments_search.cn_new_id ) as count
FROM d_search
left JOIN d_comments_search ON d_search.ne_id = d_comments_search.cn_new_id and d_search.ne_hide='1'
inner join d_search_category on d_search_category.nc_id = d_search.ne_category_id and d_search_category.nc_hide= '1'
and d_search.ne_id= $id group by d_search.ne_id");
return $result->row() ;
}
function generate_results($keyword,$row=0){
$result1 = $this->db->query("SELECT bo_id,bo_name,bo_state,bo_about FROM d_book where (bo_name like '%$keyword%' or bo_about like '%$keyword%') and bo_state = '1' limit $row,20");
$result2 = $this->db->query("SELECT au_id,au_name,au_state,au_info FROM d_author where (au_name like '%$keyword%' or au_info like '%$keyword%') and au_state = '1' limit $row,20");
$result3 = $this->db->query("SELECT pub_id,pub_name,pub_state,pub_info FROM d_publishing where (pub_name like '%$keyword%' or pub_info like '%$keyword%') and pub_state = '1' limit $row,20");
$results = array_merge($result1->result_array(),$result2->result_array(),$result3->result_array());
return $results;
}
// get total number of users
function getNumUsers($keyword)
{
$result1 = $this->db->query("SELECT bo_id,bo_name,bo_state,bo_about FROM d_book where (bo_name like '%$keyword%' or bo_about like '%$keyword%') and bo_state = '1'");
$result1 = $result1->num_rows();
$result2 = $this->db->query("SELECT au_id,au_name,au_state,au_info FROM d_author where (au_name like '%$keyword%' or au_info like '%$keyword%') and au_state = '1'");
$result2 = $result2->num_rows();
$result3 = $this->db->query("SELECT pub_id,pub_name,pub_state,pub_info FROM d_publishing where (pub_name like '%$keyword%' or pub_info like '%$keyword%') and pub_state = '1'");
$result3 = $result3->num_rows();
return $result1 + $result2 + $result3;
}
//////////////////////////////////end paging///////////////////
function get_publishing()
{
$this->db->where('pub_state','1');
$result=$this->db->get('d_publishing')->result_array();
return $result;
}
function get_author()
{
$this->db->where('au_state','1');
$result=$this->db->get('d_author')->result_array();
return $result;
}
function get_section()
{
$this->db->where('sec_state','1');
$result=$this->db->get('d_section')->result_array();
return $result;
}
function search_name()
{
$bo_name=$_POST['bo_name'];
$this->db->order_by("bo_ord","asc");
$this->db->like('bo_name',$bo_name);
return $this->db->get('d_book')->result_array();
}
function search_all() {
$publish = $this->input->post('publish');
$author = $this->input->post('author');
$sec_name = $this->input->post('section');
$sql = $this->db->query("SELECT * FROM `d_book`");
$searches = array();
if ($publish != 'choose')
$searches[] = "`bo_pub_id` = '$publish'";
if ($author != 'choose')
$searches[] = "`bo_au_id` = '$author'";
if ($sec_name != 'choose')
$searches[] = "`bo_sec_id` = '$sec_name'";
if (count($searches) > 0) {
$sql .= "WHERE " . implode(" AND ", $searches);
}
$sql .= ';';
}
}
this is controller
class Search extends front_end {
var $temp;
function __construct(){
parent::__construct();
$this->load->library('form_validation');
//echo $this->input->post("keyboard");
}
public function index()
{
$this->overview();
}
/**
* This function display all search
* #param integer $row
*/
public function overview($row=0)
{
$this->form_validation->set_rules('keyword', 'كلمة البحث', 'trim|required|xss_clean|htmlspecialchars');
$this->form_validation->run();
$this->store_keyword();
//echo $this->session->flashdata('keyword');
if ($this->session->flashdata('keyword') != ''){
$keyword=$this->session->flashdata('keyword');
$this->generate_results($this->session->flashdata('keyword'),$row);
}else{
$this->generate_results($this->input->post("keyword"),$row);
}
//$this->session->set_flashdata('keyword', $this->input->post("keyword"));
$data = $this->temp;
//$this->session->keep_flashdata('keyword');
$this->view('search/site/results', $data);
}
/**
* This function generate result of search
* #param string $keyword
* #param integer $row
*/
public function generate_results($keyword,$row=0){
$this->load->model('search/search_model','search');
$this->load->library('pagination');
$config['base_url'] = base_url().'search/search/overview/';
$config['total_rows'] = $this->search->getNumUsers($keyword);
$config['per_page'] = '20';
$config['uri_segment'] = '4';
$this->pagination->initialize($config);
$data['page'] = $row;
$data['results'] = $this->search->generate_results($keyword,$row);
$data['total_rows'] = $this->search->getNumUsers($keyword);
$data['links']=$this->pagination->create_links();
$this->temp = $data;
}
/**
* This function display detail of new
* #param integer $id
*/
public function show($id)
{
$data['new']=$this->search->show_new($id);
$count=$data['new']->ne_count_visit;
$this->search->add_count($count,$id);
$data['comments']=$this->search->show_comments($id);
$this->view('site/new', $data);
}
/**
* This function store keyword to use in search
*/
private function store_keyword(){
if($this->input->post("keyword")){
$this->session->set_userdata('keyword', $this->input->post("keyword"));
}
}
public function search_form()
{
$this->load->model('search/search_model','search');
$data['publish']=$this->search->get_publishing();
$data['author']=$this->search->get_author();
$data['section']=$this->search->get_section();
$this->view('search/site/adv_search_form',$data);
}
public function search_adv()
{
$this->load->model('search/search_model','search');
$data['bo_name']=$this->input->post('bo_name');
$data['section']=$this->input->post('section');
$data['publish']=$this->input->post('publish');
$data['author']=$this->input->post('author');
$data['result1'] = '';
$data['result2'] = '';
$data['result3'] = '';
$data['result4'] = '';
if($data['bo_name'] == NULL and $data['section']== NULL and $data['publish']==NULL and $data['author']== NULL){
$this->search_form();
}else{
if(isset($data['bo_name']) and $data['bo_name']!= NULL)
{
$data['result1'] = $this->search->search_name();
}
if(isset($data['section']) and $data['section'] != NULL)
{
$data['result2']=$this->search->search_all();
}
if(isset($data['publish']) and $data['publish'] != NULL)
{
$data['result3']=$this->search->search_all();
}
if(isset($data['author']) and $data['author']!= NULL)
{
$data['result4']=$this->search->search_all();
}
$data['no_results'] = '';
if(! $data['result1'] && !$data['result2'] && !$data['result3'] && !$data['result4']){
$data['no_results'] = TRUE;
}else{
$data['no_results'] = FALSE;
}
$this->view('search/site/search_result',$data);
}
}
}
/* End of file dashboard.php */

Answer 1

$this->db->query() doesn't store a query string for later use. It actually executes the query right away and return an object of CI_DB_mysql_result. You should build the query string before you call $this->db->query() and store it into a variable, then pass it into the method.
$sql = "SELECT * FROM `d_book` ";
$searches = array();
if ($publish != 'choose')
{
$searches[] = "`bo_pub_id` = '__some_id__'";
}
if ($author != 'choose')
{
$searches[] = "`bo_au_id` = '__some_id__'";
}
if ($sec_name != 'choose')
{
$searches[] = "`bo_sec_id` = '__some_id__'";
}
if (count($searches) > 0)
{
$sql .= "WHERE " . implode(" AND ", $searches);
}
$sql .= ';';
$this->db->query($sql);