inconsistent amount of data when I use pagination in CodeIgniter - php

Question

I want to perform a large of data using paging library in CodeIgniter. I have been implementing it and it works. But, I have a problem - amount of data per page is not consistent.
This is the simple code how Imade it...
Controller
class Buku_con extends Controller {
public function Buku_con() {
parent::__construct();
$this->load->model('buku_model');
$this->load->library('pagination'); //call pagination library
}
function getBuku() {
//count the total rows of tb_book
$this->db->select('*');
$this->db->from('tb_book');
$getData = $this->db->get('');
$a = $getData->num_rows();
$config['base_url'] = base_url().'index.php/Buku_con/getBuku/'; //set the base url for pagination
$config['total_rows'] = $a; //total rows
$config['per_page'] = '10'; //the number of per page for pagination
$config['uri_segment'] = 3; //see from base_url. 3 for this case
$config['full_tag_open'] = '<p>';
$config['full_tag_close'] = '</p>';
$this->pagination->initialize($config); //initialize pagination
$data['detail'] = $this->buku_model->getBuku($config['per_page'],$this->uri->segment(3));
$this->load->view('buku_view', $data);
}
}
Model
class Buku_model extends Model {
function Buku_model() {
parent::Model();
}
function getBuku($perPage,$uri) { //to get all data in tb_book
$title=$this->session->userdata('title');
$this->db->select('*');
$this->db->from('tb_book');
$this->db->where('title','$title');
$this->db->order_by('id','DESC');
$getData = $this->db->get('', $perPage, $uri);
if($getData->num_rows() > 0)
return $getData->result_array();
else
return null;
}
}
View
if(count($detail) > 0) {
//... html for table .....
foreach($detail as $rows) {
echo
.... $rows['id'] .....
.... $rows['title'] .....
.... $rows['author'] .....
....
}
echo $this->pagination->create_links(); ....
The paging works well, but amount of data per page is not consistent like I define in controller. I think the problem is caused by the query that I use in model - Session of title.
I want the data perform 10 data per page, but in page 1 just 5 data, page 2 just 4 data - not consistent. Maybe the problem is also in the view. What should I do? Thank you very much.

Answer 1

you have not properly calculated the offset. You may try this:
$offset = ( $this->uri->segment(3) - 1 ) * $config['per_page'];
$data['detail'] = $this->buku_model->getBuku($config['per_page'], $offset);

Answer 2

you might wanna look at this for proper pagination using codeigniter Pagination Library
https://stackoverflow.com/a/10123424/876117
You don't get all the data for each request. You need to fetch only data as specified the offset in the link generated by the pagination library.

Answer 3

Dude, there is a lot of queries on your Controller. And also on Model (of corse).
First: Try to consume almost only functions on your controller. Functions that you create on a model. Thats is the right MVC way.
And about your problem with pagination:
Try to use and abuse of GET variables. Kind, you can pass a url like that:
http://site.com/controller/function?p=2
See? "?p=2"? That way I can say to my controller that I want to see the second page os the list. You know, I can pass more GET variables, like:
http://site.com/controller/function?p=2&cat=romance&year=2010
And theres the way you will work these variables:
Lets take the second exemple ("?p=2&cat=romance&year=2010")
$page = $this->input->get('p'); // this is more secure too. avoid use $_GET or $_POST
$category = $this->input->get('cat');
$year = $this->input->get('year');
Now you can use some functions to get a list of books that matches to the values:
$data['books'] = $this->book->get_by_search($page, $category, $year);
PS: On this example, you got load a model 'book'that holds a function called 'get_by_search'. You have to do it to get the code working.
Tip: We never know how many variables a search can get. So you can create some model functions that receives those possible variables. Look:
//model Book
public function get_by_search($page = NULL, $cat = NULL, $year = NULL, $author = NULL)
{
$perpage = 10;
// the NULL is to prevent an error if the function is called without them.
if ( ! is_numeric($page) || $page < 0)
{
$qtd = $perpage;
$offset = 0;
}
else
{
$qtd = $page * perpage;
$offset = $perpage;
}
$this->db->where('category', $cat);
$this->db->where('year', $year);
return $this->db->get('books', $perpage, $offset);
// if you want to debug your queries, do the same above, but with no return
// and then use this:
echo this->db->last_query(); die; // stop here and see the query string.
}
well, I hope that it can help you. There is more to tell you but I think that its better you tell me more about your progress with the code. This answer is just a part of the solution. See? thats is not that simple, but I know how. Let me know here if you need more help, ok?
Um abraço!