what is wrong with this code - php

Question

class MyClass {
private $db;
// Constructor
function __construct() {
$this->db = new mysqli('localhost', 'root', 'root', 'Test_db');
$this->db->autocommit(FALSE);
}
// Destructor
function __destruct() {
$this->db->close();
}
// Main method
function MyFun() {
// Check for required parameters
if (isset($_POST["name"]) && isset($_POST["username"]) && isset($_POST["password"]) && isset($_POST["email"])) {
echo "Before \n";
$name = $_POST["name"];
$username = $_POST["username"];
$password = $_POST["password"];
$email = $_POST["email"];
$activation = 0;
echo "After \n";
// tracking
$stmt = $this->db->prepare("INSERT INTO users (name, username, password, email,activation) VALUES (?, ?, ?, ?, ?)");
$stmt->bind_param("is", $name, $username, $password, $email, $activation); //Line 95
$stmt->execute();
$stmt->close();
}
Output:
Before
After
Invalid request
MAMP Console:
[15-Apr-2011 15:09:10] PHP Warning: mysqli_stmt::bind_param() [<a href='function.mysqli-stmt-bind-param'>function.mysqli-stmt-bind-param</a>]: Number of elements in type definition string doesn't match number of bind variables in /Applications/MAMP/htdocs/Test/reg.php on line 95
The number is the same but I don't know why this error appears

Answer 1

$stmt->bind_param("is", $name, $username, $password, $email, $activation);
Your "definition" string ("is") contains only two definitions, integer and string ... you should have 5 in there.
$stmt->bind_param("sssss", $name, $username, $password, $email, $activation);
... for example ...

Answer 2

You are only having five ? placeholders in your query, yet you're trying to bing six values to the query.
$stmt->bind_param("is", $name, $username, $password, $email, $activation);
"is"
$name
$username
$password
$email
$activation
The format you are giving does only contain 2 definition, yet it must contain 5 to match your query. Try "sssss".

Answer 3

The "is" is the sixth variable, I suggest you remove this or add the field name in the statement:
$stmt->bind_param("is", $name, $username, $password, $email, $activation);
Either remove from bind_param:
$stmt = $this->db->prepare("INSERT INTO users (name, username, password, email,activation) VALUES (?, ?, ?, ?, ?)");
$stmt->bind_param($name, $username, $password, $email, $activation);
or add to field names:
$stmt = $this->db->prepare("INSERT INTO users (**is**, name, username, password, email,activation) VALUES (?, ?, ?, ?, ?)");
$stmt->bind_param("**is**", $name, $username, $password, $email, $activation);
or
$stmt = $this->db->prepare("INSERT INTO users (name, username, password,
email,activation) VALUES (?, ?, ?, ?, ?)");
$stmt->bind_param("issss", $name, $username, $password, $email, $activation);