When binding parameters you need to pass a variable that is used as a reference:
$var = 1;
$stmt->bind_param('i', $var);
See the manual: http://php.net/manual/en/mysqli-stmt.bind-param.php
Note that $var
doesn’t actually have to be defined to bind it. The following is perfectly valid:
$stmt->bind_param('i', $var);
foreach ($array as $element)
{
$var = $element['foo'];
$stmt->execute();
}