Codeigniter issue with controller and model

Question

I am using codeigniter 1.7.3 and I have controllers set up and working, but I am having trouble getting back a query result when I try to access a model via a controller.

I have my database configured correctly in the config area (I know this because when I intentionally mess up one of the config options I get a message saying the database cannot be accessed.)

Here's the relevant controller (SiteObj.php) code:

class SiteObj extends Controller {
     function __construct() {
          parent::Controller();
          $this->load->model('Site_model');
          $data['query'] = $this->Site_model->create_site();

          if ($data->num_rows() == 1) {
             //etc. etc.

And here is the relevant Model (site_model.php) code:

class Site_model extends Model {
    function __construct() {
        parent::Model();
        $this->load->database();
    }

    function create_site(){
        $query = $this->db->query("SELECT * FROM sites WHERE siteid = '1' LIMIT 1");

        if ($query->num_rows() > 0) {
         $row = $query->row();
         return $row;
             // etc etc

I have also tried naming the initial function Site_model instead of constructor, but with no luck. And I also tried auto-loading the database via the autoload.php file, and also by loading the database within the create_site function itself instead of the constructor function.

Here is the error message I am getting:

Fatal error: Call to a member function num_rows() on a non-object in /www/development/sunrise_ci/00ci00/application/init/siteObj.php on line 9

UPDATE: I followed the advice given by the first responder, but that didn't help.

I have since removed all references to the database connectivity in an attempt to isolate the issue. When I simply try to call the create_site() function from within the controller, I get this:

Undefined property: SiteObj::$Site_model
Fatal error: Call to a member function create_site() on a non-object

So it seems the issue is between the controller and the model, somehow they don't seem to be "talking" to each other correctly. Interestingly, I am able to see that I can pass a value through to the controller from create_site(), but I still get the error messaging along with it.

**** UPDATE 12/18 **********

Ok, first, I have amended the application/config/hooks.php file so that I can pre-load my init code ahead of all page calls. So this page has this:

$hook['pre_controller'][] = array(
        'class'    => 'SiteObj',
        'function' => '__construct',
        'filename' => 'siteObj.php',
        'filepath' => 'init'
    );

Next, I have a default controller handling all page calls. It's located at controllers/page.php and here's that code:

class Page extends Controller {
        // I am the core controller for the application.
        function _remap() {
            $mysite = new SiteObj();
        }
    }

This calls the init object that I have set up in application/init/siteobj.php. Here's that code:

class SiteObj extends Controller {
        function __construct() {
            parent::Controller();
            $this->load->model('Site_model');
            $data = $this->Site_model->create_site();
            if ($data){
                $this->siteid = $data->siteid;
            } else {
                $this->siteid = 0;
            }
        }
    }

Finally, here's the model code in models/site_model.php:

class Site_model extends Model {
        function Site_model() {
            parent::Model();
            $this->load->database();
        }

        public function create_site(){
            // I load the site data from the database and send the result to the controller
            $query = $this->db->query("SELECT * FROM sites WHERE siteid = '1' LIMIT 1");
            if ($query->num_rows() == 1) {
                return $query->row();
            }
        }
    }

I get this error:

Undefined property: SiteObj::$Site_model
Fatal error: Call to a member function create_site() on a 
non-object in 
/www/development/sunrise_ci/00ci00/application/init/siteObj.php 
on line 7

Thanks in advance!

Gary

Colin Brock · Accepted Answer · 2010-12-18 18:56:19Z

2

Update based on updated code in original question:

Keep in mind that CodeIgniter's Hooks Class is initialized before the Loader Class, so your pre_controller hook is instantiating SiteObj and trying to call Site_model->create_site() before Site_model has been loaded via the Loader Class.

It's throwing an error because you can't call a method on an object that doesn't exist yet. In this case Site_model is the object that doesn't exist yet.

Remember that you can check your log files (located in /system/logs/) to see the order in which resources are executed. It might also be helpful to review the CodeIgniter Application Flow Chart.

Hope that helps!

End Update

The num_rows() method can only be used on the entire $query result object like you have in your Site_model:

$query = $this->db->query("SELECT * FROM sites WHERE siteid = '1' LIMIT 1");

if ($query->num_rows() > 0) {
        // do stuff
}

However, currently your create_site() method in your Site_model is returning a single row (return $row;) from the result object, and then you're trying to call num_rows() on that single row in your SiteObj controller.

There really is no need to do this because $query->row(); will always return a single result row.

If you did absolutely want to call num_rows() from inside your controller (again, there's really no point since $query->row() will always return only one row), you must return the entire $query result object like this:

$query = $this->db->query("SELECT * FROM sites WHERE siteid = '1' LIMIT 1");

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

Then in your SiteObj controller:

$this->load->model('Site_model');

$data = $this->Site_model->create_site();

if ($data->num_rows() == 1) {
    //etc. etc.
}

Hope that helps - if not let me know. It doesn't look like your code is too far off! For reference, check out the num_rows() method and the row() method.

edited Dec 18, 2010 at 18:56

answered Dec 18, 2010 at 5:00

Colin Brock

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9 Comments

Colin Brock Over a year ago

To anyone reading this, there was another answer posted that the OP is referring to in the original question.

Gary Over a year ago

Hi Colin, thanks for your feedback -- it's very similar to what the original responder said. But the issue seems to be a different one that I originally thought (see the UPDATE in my original post). Even when I take out all the database connection stuff I get this error: "Call to a member function create_site() on a non-object". Am I doing something wrong when I instantiate the object? Thanks!

Gary Over a year ago

I think I am onto something: it seems that when I take everything out of the construct function except the parent::Controller() or the parent::Model() call, things start behaving more as expected. Was that the issue? Can I not put any other code in that construct function?

Colin Brock Over a year ago

@Gary: Yes, you can put other code in the constructor - that's not a problem. I quickly set up a CodeIgniter test instance with nothing more than the controller, model, and db table you mentioned in your question and everything is working fine. The only thing I changed was I removed the call to num_rows() in the controller. Is there more code you can post? Or can you post your most updated code?

Colin Brock Over a year ago

@Gary: The error you reported in your update suggests you aren't loading your model anymore? You can't call create_site() without having first done $this->load->model('Site_model');. And yes, you can do that in the constructor.

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