Call to a member function fetch() on a non-object

lookee · December 15, 2008

Below is my complete code (less the connection to the database)

When I run the following code, I get the following error:

Call to a member function fetch() on a non-object in line 138

If I comment out the PROBLEM LINES, the shopping cart partially displays onscreen, but the content of shopping cart passed from the previous .php screen is not passed in completion.

What I need are the mysql commands or something to replace PROBLEM LINES that will access the information passed from the previous shopping cart page.

Any help would be greatly appreciated.

Thanks!


// Select the Database
$db_select=mysql_select_db($db_name);
if (!$db_select)
{
die ("Couldn't select the database: <br/>". mysql_eror());
}




// Process actions
$cart = $_SESSION['cart'];
$action = $_GET['action'];
switch ($action) {
case 'add':
	if ($cart) {
		$cart .= ','.$_GET['id'];
	} else {
		$cart = $_GET['id'];
	}
	break;
case 'delete':
	if ($cart) {
		$items = explode(',',$cart);
		$newcart = '';
		foreach ($items as $item) {
			if ($_GET['id'] != $item) {
				if ($newcart != '') {
					$newcart .= ','.$item;
				} else {
					$newcart = $item;
				}
			}
		}
		$cart = $newcart;
	}
	break;
case 'update':
if ($cart) {
	$newcart = '';
	foreach ($_POST as $key=>$value) {
		if (stristr($key,'qty')) {
			$id = str_replace('qty','',$key);
			$items = ($newcart != '') ? explode(',',$newcart) : explode(',',$cart);
			$newcart = '';
			foreach ($items as $item) {
				if ($id != $item) {
					if ($newcart != '') {
						$newcart .= ','.$item;
					} else {
						$newcart = $item;
					}
				}
			}
			for ($i=1;$i<=$value;$i++) {
				if ($newcart != '') {
					$newcart .= ','.$id;
				} else {
					$newcart = $id;
				}
			}
		}
	}
}
$cart = $newcart;
break;
}
$_SESSION['cart'] = $cart;
?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Shopper Shopper</title>
<link rel="stylesheet" href="css/styles.css" />
</head>

<body>

<div id="shopper">

<h1>Deliva's Shopping Cart</h1>

<?php
function writeShoppingCart() {
$cart = $_SESSION['cart'];
if (!$cart) {
	return '<p>You have no items in your shopping cart</p>';
} else {
	// Parse the cart session variable
	$items = explode(',',$cart);
	$s = (count($items) > 1) ? 's':'';
	return '<p>You have <a href="cart.php">'.count($items).' item'.$s.' in your shopping cart</a></p>';
}
}
echo writeShoppingCart();

?>

</div>

<div id="contents">

<h1>Review Quantityh1>

<?php

function showCart() {
global $db;
$cart = $_SESSION['cart'];
if ($cart) {
	$items = explode(',',$cart);
	$contents = array();
	foreach ($items as $item) {
		$contents[$item] = (isset($contents[$item])) ? $contents[$item] + 1 : 1;
	}
	$output[] = '<form action="cart.php?action=update" method="post" id="cart">';
	$output[] = '<table>';
	foreach ($contents as $id=>$qty) {


PROBLEM LINE ---->  $row = $result->fetch();

PROBLEM LINE ---->   extract($row);

		$output[] = '<tr>';
		$output[] = '<td><a href="cart.php?action=delete&id='.$id.'" class="r">Remove</a></td>';
		$output[] = '<td>'.$title.' by '.$author.'</td>';
		$output[] = '<td>£'.$price.'</td>';
		$output[] = '<td><input type="text" name="qty'.$id.'" value="'.$qty.'" size="3" maxlength="3" /></td>';
		$output[] = '<td>£'.($price * $qty).'</td>';
		$total += $price * $qty;
		$output[] = '</tr>';
	}
	$output[] = '</table>';
	$output[] = '<p>Grand total: <strong>£'.$total.'</strong></p>';
	$output[] = '<div><button type="submit">Update cart</button></div>';
	$output[] = '</form>';
} else {
	$output[] = '<p>You shopping cart is empty.</p>';
}
return join('',$output);
}


echo showCart();





?>

xtopolis · December 15, 2008

I don't see where $result is being defined anywhere in this script.. other than when you try to fetch(). Did you forget to query the database first?

lookee · December 15, 2008

Okay, thanks... I now defined $result in the line above, and I call the function fetch several lines above, but I still get the error..

Fatal error: Call to a member function fetch() on a non-object

Is the non-object $row, or is the non-object something in the database?

My head hurts.

Thanks for any help.



<?php
function writeShoppingCart() {
$cart = $_SESSION['cart'];
if (!$cart) {
	return '<p>You have no items in your shopping cart</p>';
} else {
	// Parse the cart session variable
	$items = explode(',',$cart);
	$s = (count($items) > 1) ? 's':'';
	return '<p>You have <a href="cart.php">'.count($items).' item'.$s.' in your shopping cart</a></p>';
}
}
echo writeShoppingCart();

?>

</div>

<div id="contents">

<h1>REVIEW QUANTITY</h1>

<?php
    * Checks for MySQL errors
    * @return boolean
    * @access public
    */
    function isError () {
        if ( $this->connectError )
            return true;
        $error=mysql_error ($this->dbConn);
        if ( empty ($error) )
            return false;
        else
            return true;
    }

    /**
    * Returns an instance of MySQLResult to fetch rows with
    * @param $sql string the database query to run
    * @return MySQLResult
    * @access public
    */
function query($sql) 

	{
        if (!$queryResource=mysql_query($sql,$this->dbConn))
            trigger_error ('Query failed: '.mysql_error($this->dbConn).
                           ' SQL: '.$sql);
        return new MySQLResult($this,$queryResource);
	}
}


/**
* MySQLResult Data Fetching Class
* @access public
* @package SPLIB
*/
class MySQLResult {
    /**
    * Instance of MySQL providing database connection
    * @access private
    * @var MySQL
    */
    var $mysql;

    /**
    * Query resource
    * @access private
    * @var resource
    */
    var $query;

    /**
    * MySQLResult constructor
    * @param object mysql   (instance of MySQL class)
    * @param resource query (MySQL query resource)
    * @access public
    */
    function MySQLResult(& $mysql,$query) {
        $this->mysql=& $mysql;
        $this->query=$query;
    }

    /**
    * Returns the number of rows selected
    * @return int
    * @access public
    */
    function size () {
        return mysql_num_rows($this->query);
    }

    /**
    * Returns the ID of the last row inserted
    * @return int
    * @access public
    */
    function insertID () {
        return mysql_insert_id($this->mysql->dbConn);
    }
    
    /**
    * Checks for MySQL errors
    * @return boolean
    * @access public
    */
    function isError () {
        return $this->mysql->isError();
    }
}

    /**
    * Fetches a row from the result
    * @return array
    * @access public
    */
function fetch () {
        if ( $row=mysql_fetch_array($this->query,MYSQL_ASSOC) ) {
            return $row;
        } else if ( $this->size() > 0 ) {
            mysql_data_seek($this->query,0);
            return false;
        } else {
            return false;
        }
    }



// $result		=	mysql_query($query);
function showCart() {
global $db;
$cart = $_SESSION['cart'];
if ($cart) {
	$items = explode(',',$cart);
	$contents = array();
	foreach ($items as $item) {
		$contents[$item] = (isset($contents[$item])) ? $contents[$item] + 1 : 1;
	}
	$output[] = '<form action="cart.php?action=update" method="post" id="cart">';
	$output[] = '<table>';


	foreach ($contents as $id=>$qty) {
		$sql = 'SELECT * FROM packages WHERE id = '.$id;
		$result = mysql_query($sql);


PROBLEM LINE --->	$row = $result->fetch();		
		extract($row);


		$output[] = '<tr>';
		$output[] = '<td><a href="cart.php?action=delete&id='.$id.'" class="r">Remove</a></td>';
		$output[] = '<td>'.$title.' by '.$author.'</td>';
		$output[] = '<td>£'.$price.'</td>';
		$output[] = '<td><input type="text" name="qty'.$id.'" value="'.$qty.'" size="3" maxlength="3" /></td>';
		$output[] = '<td>£'.($price * $qty).'</td>';
		$total += $price * $qty;
		$output[] = '</tr>';
	}
	$output[] = '</table>';
	$output[] = '<p>Grand total: <strong>£'.$total.'</strong></p>';
	$output[] = '<div><button type="submit">Update cart</button></div>';
	$output[] = '</form>';
} else {
	$output[] = '<p>You shopping cart is empty.</p>';
}
return join('',$output);
}


echo showCart();


?>

[\code]

lookee · December 15, 2008

I have this shopping cart almost running, but it doesn't display the actual names of the contents within the database.

I've indicated below where I'm having problems ... What code do I insert to display the database contents of the related Ids? I have tried a variety of things, but none are working.

Any help would be greatly appreciated.



function connectToDb () -- specifics removed....


// Select the Database
$db_select=mysql_select_db($db_name);

if (!$db_select)
{
die ("Couldn't select the database: <br/>". mysql_eror());
}


    function isError () {
        if ( $this->connectError )
            return true;
        $error=mysql_error ($this->dbConn);
        if ( empty ($error) )
            return false;
        else
            return true;
    }

    /**
    * Returns an instance of MySQLResult to fetch rows with
    * @param $sql string the database query to run
    * @return MySQLResult
    * @access public
    */
function query($sql) 

	{
        if (!$queryResource=mysql_query($sql,$this->dbConn))
            trigger_error ('Query failed: '.mysql_error($this->dbConn).
                           ' SQL: '.$sql);
        return new MySQLResult($this,$queryResource);
	}
}


/**
* MySQLResult Data Fetching Class
* @access public
* @package SPLIB
*/
class MySQLResult {
    /**
    * Instance of MySQL providing database connection
    * @access private
    * @var MySQL
    */
    var $mysql;

    /**
    * Query resource
    * @access private
    * @var resource
    */
    var $query;

    /**
    * MySQLResult constructor
    * @param object mysql   (instance of MySQL class)
    * @param resource query (MySQL query resource)
    * @access public
    */
    function MySQLResult(& $mysql,$query) {
        $this->mysql=& $mysql;
        $this->query=$query;
    }

    /**
    * Returns the number of rows selected
    * @return int
    * @access public
    */
    function size () {
        return mysql_num_rows($this->query);
    }

    /**
    * Returns the ID of the last row inserted
    * @return int
    * @access public
    */
    function insertID () {
        return mysql_insert_id($this->mysql->dbConn);
    }
    
    /**
    * Checks for MySQL errors
    * @return boolean
    * @access public
    */
    function isError () {
        return $this->mysql->isError();
    }
}

    /**
    * Fetches a row from the result
    * @return array
    * @access public
    */
function fetch () {
        if ( $row=mysql_fetch_array($this->query,MYSQL_ASSOC) ) {
            return $row;
        } else if ( $this->size() > 0 ) {
            mysql_data_seek($this->query,0);
            return false;
        } else {
            return false;
        }
    }


$result = mysql_query($sql);

// $result		=	mysql_query($query);
function showCart() {
$cart = $_SESSION['cart'];
if ($cart) {
	$items = explode(',',$cart);
	$contents = array();
	foreach ($items as $item) {
		$contents[$item] = (isset($contents[$item])) ? $contents[$item] + 1 : 1;
	}

                         NOT SURE WHAT TO PUT HERE TO SHOW CONTENTS....

     $output[] = '<form action="cart.php?action=update" method="post" id="cart">';
	$output[] = '<table>';


	foreach ($contents as $id=>$qty) {
		$sql = 'SELECT * FROM packages WHERE id = '.$id;
		$result = mysql_query($sql);

		$output[] = '<tr>';
		$output[] = '<td><a href="cart.php?action=delete&id='.$id.'" class="r">Remove</a></td>';
		$output[] = '<td>'.$size.' by '.$width.'</td>';
		$output[] = '<td>£'.$price.'</td>';
		$output[] = '<td><input type="text" name="qty'.$id.'" value="'.$qty.'" size="3" maxlength="3" /></td>';
		$output[] = '<td>£'.($price * $qty).'</td>';
		$total += $price * $qty;
		$output[] = '</tr>';
	}
	$output[] = '</table>';
	$output[] = '<p>Grand total: <strong>£'.$total.'</strong></p>';
	$output[] = '<div><button type="submit">Update cart</button></div>';
	$output[] = '</form>';
} else {
	$output[] = '<p>You shopping cart is empty.</p>';
}
return join('',$output);
}

echo showCart();





?>

Thanks!

fenway · December 15, 2008

Impossible to debug this way... this is a magic object class.

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