PDO PHP Update Script not working - php

Question

I've searched on stackoverflow and other sources but I cant seem to find the issue that is preventing my PHP script from working.
Look at the echo_sql. It produces a healthy update statement which when run updates the database with no problem. Here is a sample:
update waste set waste_name=1 where id =82;
However, when the script is run, it does not apply changes to the database. Here is the script:
if ($_SERVER['REQUEST_METHOD'] == "POST") {
try {
$waste_id = $_POST['waste_id'];
$sql = new db;
$sql->beginTransaction();
$waste_name = $_POST['waste_name'];
$sql->query("update waste set waste_name=:waste_name where id =:waste_id;");
$echo_sql = "update waste set waste_name=$waste_name where id =$waste_id;";
echo $echo_sql;
$sql->bind(':waste_name', $waste_name);
$sql->execute();
$sql->endTransaction();
} catch (Exception $e) {
$sql->rollBack();
echo "Failed: " . $e->getMessage();
}
}
Additional details:
errorCode() = 00000
DB Class:
class db
{
private $stmt;
private $dbc;
public function __construct()
{
$u = "root";
$p = "";
try {
$this->dbc = new PDO('mysql:host=127.0.0.1;dbname=wimsdb', $u, $p);
$this->dbc->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
$e->getMessage();
}
}
public function bind($param, $value, $type = NULL)
{
$this->stmt->bindParam($param, $value, $type);
}
public function beginTransaction()
{
return $this->dbc->beginTransaction();
}
public function rollBack()
{
return $this->dbc->rollBack();
}
public function endTransaction()
{
return $this->dbc->commit();
}
public function cancelTransaction()
{
return $this->dbc->rollBack();
}
public function execute()
{
try {
return $this->stmt->execute();
} catch (PDOException $e) {
return $e->errorInfo;
}
}
public function errorCode()
{
return $this->stmt->errorCode();
}
public function query($query)
{
$this->stmt = $this->dbc->prepare($query);
}
}
Please offer your suggestions on how this could be resolved.

Answer 1

You need to bind the :waste_id too:
$waste_id = $_POST['waste_id'];
$sql = new db;
$sql->beginTransaction();
$waste_name = $_POST['waste_name'];
$sql->query("update waste set waste_name=:waste_name where id =:waste_id;");
$sql->bind(':waste_name', $waste_name);
$sql->bind(':waste_id', $waste_id);
Any time you have an issue like this your error checking should return a meaningful message letting you know where the error is and likely what the error is. You should be able to check your error logs for details and/or output them to your screen during testing.

Answer 2

Add waste_id. To avoid missing parameters, I like putting the parameteers into the execute method. The bind method could be defined anywhere in the code so I had to look through your code and make sure waste_id binding wasn't defined somewhere else. When it's in the execute method, you can quickly see all parameters being defined there...it's also a tad more concise...but both have their uses.
if ($_SERVER['REQUEST_METHOD'] == "POST") {
try {
$waste_id = $_POST['waste_id'];
$sql = new db;
$sql->beginTransaction();
$waste_name = $_POST['waste_name'];
$sql->query("update waste set waste_name=:waste_name where id =:waste_id;");
$echo_sql = "update waste set waste_name=$waste_name where id =$waste_id;";
echo $echo_sql;
//just because I like this syntax for being concise and clear :)
$sql->execute(array(
'waste_id' => $waste_id,
'waste_name' => $waste_name
));
$sql->endTransaction();
} catch (Exception $e) {
$sql->rollBack();
echo "Failed: " . $e->getMessage();
}