Question

I have a problem with producing a Register using my MySQLI Code. The tables/connection variable is matching up, and the correct variables being passed through the query is populated with expected strings, when running a query or prepare & execute when performing any type of query, I get returned with the following:

Fatal error: Call to a member function query() on a non-object in
/var/www/New/API/FormValidations.php on line 40

My code is as followed:

$Query = $STD->prepare("SELECT * FROM Users WHERE Username='$Username'");
$Query->execute();
$Number = $Query->num_rows;
if ($Number !== 0)
{
    echo "Username Already In Use";
}
else
{
$Insert_User = $STD->prepare("INSERT INTO Users ('Username', 'Password') VALUES ('$Username', '$Password)");
$Insert_User->execute();
echo "Account Created!";
}

Here is My Connection Script:

$STD = new mysqli('localhost', 'root', 'xxxxx', 'SLMS');
$AccessCon = new mysqli('localhost', 'root', 'xxxxx', 'DBAccess');

if ($AccessCon->connect_error) {
    die("Access Has Been Revoked. Please Contact Administration");
}

if ($STD->connect_error) {
    die("Standard Access Has Been Revoked. Please Contact Administration"); 
}

and my SQL Table for Users:

CREATE TABLE IF NOT EXISTS `Users` (
  `ID` int(255) NOT NULL AUTO_INCREMENT,
  `Username` varchar(255) NOT NULL,
  `Password` text NOT NULL,
  PRIMARY KEY (`ID`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ;

I have tried commenting out all my query code, and running

$Query = $STD->query("SHOW TABLES");
$Results = $STD->fetch_array(MYSQLI_ASSOC);

this still returned an error, on my $Query variable.

I have also tried modifying my code to search for something that is already present in the database:

$Query = $STD->prepare("SELECT * FROM Users WHERE Username='Test'");

and tried to enclose my $Username As followed:

$Query = $STD->prepare("SELECT * FROM Users WHERE Username='{$Username}'");

This has performed No Success. I was wondering if someone could shed some light on this situation?

Edit:

Commenting out the entire script and just running:

$Query = $STD->query("SHOW TABLES");
$test = $Query->fetch_array(MYSQLI_ASSOC);
print_r($test);

Returns a result.

UPDATE:

I have modified my code to:

$Query = $STD->prepare("SELECT * FROM Users WHERE Username=?");
                $Query->bind_param("s", $Username);
                $Query->execute();

Final Update:

Fatal error: Call to a member function bind_param() on a non-object
in /var/www/New/Register.php on line 45

This is the new Error.

The offending lines:

            $Insert_User = $STD->prepare("INSERT INTO Users ('Username', 'Password') VALUES (?, ?)");
                $Insert_User->bind_param("ss", $Username, $Password);
            $Insert_User->execute();

Answer 1

When using prepare you have to bind the varables that hold your values.

Example:

 $city = "Amersfoort";

/* create a prepared statement */
if ($stmt = $mysqli->prepare("SELECT District FROM City WHERE Name=?")) {

    /* bind parameters for markers */
    $stmt->bind_param("s", $city);

    /* execute query */
    $stmt->execute();

    /* bind result variables */
    $stmt->bind_result($district);

    /* fetch value */
    $stmt->fetch();

    printf("%s is in district %s\n", $city, $district);

    /* close statement */
    $stmt->close();
}

here is link to prepared statements

Update

this:

$Query = $STD->prepare("SELECT * FROM Users WHERE Username=s");

should be:

$Query = $STD->prepare("SELECT * FROM Users WHERE Username=?");

this:

$Insert_User = $STD->prepare("INSERT INTO Users ('Username', 'Password') VALUES ('U', 'P)");

should be:

$Insert_User = $STD->prepare("INSERT INTO Users ('Username', 'Password') VALUES (?, ?)");

this :

$Insert_User->bind_param('U', $Username);
$Insert_User->bind_param('P', $Password);

should be this:

$Insert_User->bind_param('ss', $Username,$Password);