PDO $db object "non-object" error?

[Eggzorcist]

I made a small script and it says that my database object isn't an object.

 

I connect to my pdo database via:

<?php

try {
$db = new PDO("mysql:host=localhost;dbname=database", "root", "root"); 
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
}  
catch(PDOException $e) {  

echo $e->getMessage();
  
}

?>

 

 

The error I get is

 

Notice: Undefined variable: db in /Users/JPFoster/Sites/jobiji_sandbox/extensions/tasks.php on line 21

Fatal error: Call to a member function query() on a non-object in /Users/JPFoster/Sites/jobiji_sandbox/extensions/tasks.php on line 21

 

 

 

here's where the error is

$grabber = $db->query('SELECT * WHERE user_id =' . $userid);	
	$grabber->setFetchMode(PDO::FETCH_OBJ);

	while ( $row = $grabber->fetch() ){

		$display = '<div>Task Name: ' . $row->name .'</div>';
		$display .= '<div>Task Details: <p>'. $row->details  .'</p></div>';
		//$display .= '<div>'. $this->checkifDone($row->task_status) .'</div>';
		$display .= '<div>Task Due: '. $row->task_due . '</div>';
		echo $display;
	}

 

 

could anyone tell me where this issue is originating I followed a fairly simple tutorial that didn't seem to work.

 

 

Thanks!

 

[PFMaBiSmAd]

It would really help if you showed the code between those two points.

 

If $db is not defined, you are either un-setting it or you have a variable scope problem.

[Eggzorcist]

here is my class

 

Its probably a variable scope issue, how do I go to fix this? Must I put a PDO object in all my objects that will use the database?

 

class fetcher {

function checkifDone( $value ){
	if ( $value == 0 ) {
		echo 'Not Done';
	} elseif ( $value == 1 ){
		echo 'Done';
	}
}

function grab_tasks( $userid ){

	$grabber = $db->query('SELECT * WHERE user_id =' . $userid);	
	$grabber->setFetchMode(PDO::FETCH_OBJ);

	while ( $row = $grabber->fetch() ){

		$display = '<div>Task Name: ' . $row->name .'</div>';
		$display .= '<div>Task Details: <p>'. $row->details  .'</p></div>';
		//$display .= '<div>'. $this->checkifDone($row->task_status) .'</div>';
		$display .= '<div>Task Due: '. $row->task_due . '</div>';
		echo $display;
	}
}

}

 

 

[PFMaBiSmAd]

You would generally just pass the $db object into your class when you create an instance of your class. In your class constructor, store it in a class variable that you can then reference in any of the methods in your class -

 

$what_ever = new fetcher($db); // pass the db object into the instance of your class.

 

 

 

 

[Eggzorcist]

Do I have to catch the variable in my object somehow? I tried adding the variable in the object creation parameter but I still get the same errors.

[PFMaBiSmAd]

Someone already stated you would need to store it in a class variable -

In your class constructor, store it in a class variable that you can then reference in any of the methods in your class

[Eggzorcist]

I'm a little bit confused about how I should reference it in my __contruct() from simply passing it on in the new fetcher() parameters.

 

Its the first time I use PDO in an object and I'm wondering what is the most ideal and practical method in doing this correctly.

 

Thank you very much!

[PFMaBiSmAd]

Setting and referencing class variables are some of the basics you should know before attempting to use a class. This has nothing to do with using PDO in an object -

 

<?php
class fetcher {

private $pdo; // class variable for PDO object

function __construct($db){
	$this->pdo = $db; // save the passed $db parameter into the class variable
   }

function grab_tasks($userid){
	$grabber = $this->pdo->query('SELECT * WHERE user_id =' . $userid); // reference the ->query() method of the class variable
	....
}
}

// instance of your db class
$db = new PDO("mysql:host=localhost;dbname=database", "root", "root");
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 

// instance of your class
$what_ever = new fetcher($db); // pass the db object into the instance of your class.

?>

[Eggzorcist]

I made the changes and I now understand the double referencing. However it still says that the query part of it is a non-object. How is this so?

Fatal error: Call to a member function query() on a non-object in .../extensions/tasks.php on line 24

 

Here is my updated php code:

<?php
try {
$db = new PDO("mysql:host=localhost;dbname=dbsanbox", "root", "root"); 
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
}  
catch(PDOException $e) {  

echo $e->getMessage();
  
}



$userval = '2';

class fetcher {

private $pdo;

function __contruct($db){
	$this->pdo = $db;
}

function checkifDone( $value ){
	if ( $value == 0 ) {
		echo 'Not Done';
	} elseif ( $value == 1 ){
		echo 'Done';
	}
}

function grab_tasks( $userid ){

	$grabber = $this->pdo->query('SELECT * WHERE user_id =' . $userid);	
	$grabber->setFetchMode(PDO::FETCH_OBJ);

	while ( $row = $grabber->fetch() ){

		$display = '<div>Task Name: ' . $row->name .'</div>';
		$display .= '<div>Task Details: <p>'. $row->details  .'</p></div>';
		//$display .= '<div>'. $this->checkifDone($row->task_status) .'</div>';
		$display .= '<div>Task Due: '. $row->task_due . '</div>';
		echo $display;
	}
}

}


$fetcher = new fetcher($db);
$fetcher->grab_tasks($userval);


?>

 

[PFMaBiSmAd]

You managed to miss-spell construct