如何将mySQL转换为PDO

Question

I have this php script for posting announcements to a database using mySQL. I'd like to change it to use PDO.

The code I have originally is here:

<?php
require_once"connection.php";
    session_start();

if(isset($_POST['annForm'])) 
{

$userID=$_SESSION['sessionUser'];
$idQuery=mysql_query("SELECT adminID FROM administrator WHERE username='$userID'");         
$adminID=mysql_fetch_array($idQuery);       


$genAnnouncement=$_POST['annForm'];
$genAnnouncement=mysql_real_escape_string($genAnnouncement);
$addGenAnnQuery="INSERT INTO generalannouncement (adminID, genAnnouncement) VALUES('$adminID[0]','$genAnnouncement')";
$announcementAdded=mysql_query($addGenAnnQuery);
if(!$announcementAdded)
{
    echo 'Could Not Add Announcement, Try Again Later.<br>';
    echo mysql_error();
}
    else
        echo 'Announcement Added Successfully.<br>';
        header( "refresh:500;url=adminsHomepage.php" );
        return;
        mysql_close($con);  
}   
?>

I have modified the code to use PDO but I am getting errors now on line 24 with undefined index $adminID[0] and line 25 with Integrity constraint violation: 1048 Column 'adminID' cannot be null. The modified code is as follows:

require_once"connection.php";

session_start();


if(isset($_POST['annForm'])) 
{
$userID=$_SESSION['sessionUser'];   
$idQuery= $conn->prepare("SELECT adminID FROM administrator WHERE username='$userID'");
$idQuery->execute();
$adminID= $idQuery->fetch();    

$genAnnouncement=$_POST['annForm'];


if (isset($genAnnouncement)) 
{
$sql = "INSERT INTO generalannouncement (adminID, genAnnouncement)
           VALUES (:adminID, :genAnnouncement)";
$stmt = $conn->prepare($sql);
$stmt->execute(array(
    ':adminID' => $_POST['$adminID[0]'],
    ':genAnnouncement' => $_POST['annForm']));

echo 'Announcement Added Successfully.<br>';
header( "refresh:500; url= adminsHomepage.php");
return;
}}

Answer 1

In your original MySQL_ query you have:

$addGenAnnQuery = "
        INSERT INTO generalannouncement 
                    (adminID, genAnnouncement) 
             VALUES ('$adminID[0]','$genAnnouncement')
";

So, if your old query work, new execute must be this:

$stmt->execute(array(
    ':adminID' => $adminID[0],
    ':genAnnouncement' => $genAnnouncement));