如何在CodeIgniter 2.1的数据库API中实现搜索和分页？

Question

I am having trouble with a search feature on a site I built with Codeigniter 2.1. Specifically, I am having trouble with pagination and limiting to 15 items per page.

My controller:

              public function program_search()
          {
      if ($this->input->post('term')){
        $this->front->set('title', 'Search Results');
        $this->front->set('res' ,  $this->wc_search->search($this->input->post('term')));

        $this->load->library('pagination');

        $config['base_url'] = base_url().'/site/program_search_results/';

        $this->db->where('JobRef',$this->input->post('term'));
        $this->db->or_where('WorkType',$this->input->post('term'));
        $this->db->or_where('Parish',$this->input->post('term'));
        $this->db->or_where('Location',$this->input->post('term'));

        $config['total_rows'] = $this->db->count_all_results('wc_program');
        $config['per_page'] = 10;
        $config['num_links'] = 20;
        $config['full_tag_open'] = '<div id="pagination">';
        $config['full_tag_close'] = '</div>';

        $this->pagination->initialize($config);     

        $this->front->buffer('content', 'site/program_search_results');
        $this->front->render();
    }
    else
    {
        $this->front->set('title', 'Program Search');
        $this->front->buffer('content', 'site/program_search');
        $this->front->render();
    }
}

Then in my model I have:

            public function search($term)
        {
    $data = array();
    $this->default_select();
    $this->db->like('JobRef', $term);
    $this->db->or_like('Area', $term);
    $this->db->or_like('Parish', $term);
    $this->db->or_like('WorkType', $term);
    $this->db->or_like('Location', $term);

    $this->default_order_by();
    //$this->db->limit(15);
    $q = $this->db->get('wc_program');
        if ($q->num_rows() > 0)
        {
            foreach ($q->result_array() as $row)
            {
                $data[] = $row;
            }
        }
    $q->free_result();
    return $data;
}

How do I get the pagination to work based on this code? I don't really want to alter the code already there as the search works fine. I just need it to show 15 records per page for whatever term is searched for.

Answer 1

Let's see if I can walk you through the issues:

1. Your search query needs a LIMIT (which you have commented out...and it's missing the offset...).
2. You need to pass your POST page parameter ( $this->input->post('page') ) to your search model, so you know which page you are on, in order to compute the LIMIT part of your search model's query. Let's say you call it $current_page in your model.
3. Why does your count_all_results query not match your search model's query? They should match with the same WHERE conditions (except the count query would not have the LIMIT you are going to add to the search model's query).
4. To compute the LIMIT (limit and offset):
   1. $limit = 15;
   2. $offset = $limit * $current_page - $limit;
   3. if($offset < 0){$offset = 0;}
5. Now your limit is: $this->db->limit($offset, $limit); for the search model's query.

Hope that helps!

Answer 2

Pass your per_page & num_links into the search() to calculate a LIMIT & OFFSET for your query

You'll need to do some simple math to calculate the offset

Answer 3

As David Graham says, you're missing your LIMIT and OFFSET. The CodeIgniter pagination is fairly basic, since the underlying "ActiveRecord" is itself very basic (in essence, a query builder, NOT an ORM).

So, you need to think on the SQL level, how do you get "pages" of results that you want.

Below I am including sample code from one of my projects.

CONTROLLER:

    // set up pagination

    $itemsPerPage = 20;
    $totalItems = $this->Location_model->count_locations( $locationName, $locationType, $locationParent );

    // get itemStartIndex from URL if specified, otherwise default to 0
    if ( $this->uri->segment(3) )
    {
        $itemStartIndex = $this->uri->segment(3);
    }
    else
    {
        $itemStartIndex = '0';
    }

    $this->load->library('pagination');

    $config['base_url'] = site_url('admin/locations');
    $config['total_rows'] = $totalItems;
    $config['per_page'] = $itemsPerPage;
    $config['uri_segment'] = 3;

    // store offset in case user triggers a function and we want to come back to same page
    $this->session->set_flashdata('pagination_offset', $itemStartIndex);

    $this->pagination->initialize($config); 

    $data['pagination'] = $this->pagination->create_links();

    // get current locations from database
    $records = $this->Location_model->get_locations( $locationName, $locationType, $locationParent, $itemStartIndex, $itemsPerPage );

    ...

    // now $records gets passed to view for display

MODEL:

function count_locations($locationName = '', $locationType = '', $locationParent = '')
{
    $this->db->select('id');
    if ( $locationName != '' )
    {
        $this->db->like('name', $locationName);
    }
    if ( $locationType != '')
    {
        $this->db->where('location_type', $locationType);
    }
    if ( $locationParent != '')
    {
        $this->db->where('parent_id', $locationParent);
    }

    $query = $this->db->get('locations');

    return $query->num_rows();
}

function get_locations($locationName = '', $locationType = '', $locationParent = '', $startIndex = '0', $limit = '')
{
    $this->db->select('*');
    if ( $locationName != '' )
    {
        $this->db->like('name', $locationName);
    }
    if ( $locationType != '')
    {
        $this->db->where('location_type', $locationType);
    }
    if ( $locationParent != '')
    {
        $this->db->where('parent_id', $locationParent);
    }

    $this->db->order_by('name', 'asc');
    $query = $this->db->get('locations', $limit, $startIndex);

    if ($query->num_rows() > 0)
    {
        return $query;
    }
    else
    {
        return FALSE;
    }
}

Notice that my method to do the query has the optional parameters $startIndex and $limit. These are MANDATORY for paging to work. The URI segment (in my case, segment 3) is going to directly tell your controller what OFFSET to use, and the per_page that you specify translates to the LIMIT (which in my case I use $itemsPerPage to store since it's referenced multiple times - actually I use a global value in my case but I hard coded it here for easier reference).

Note you will also need a count method. You COULD just use your same query, load ALL results, and count it in the controller, but I like to use a separate count method that only generates a minimal query using my WHERE restrictions and selecting just COUNT('id'), which speeds it up considerably. (the downside of course is it's an anti-pattern to DRY since the same query code must be defined twice, once for your count method and once for the data querying method)

NOTE ON YOUR CODE

Instead of specifying those or_where statements in the controller, I would put them in the model, under a method that describes your search. This sort of search logic should definitely be in the model - the controller should only be accepting the routing, passing the inputs to the model, and then setting up the pagination and view with the results.