Cannot pass parameter by reference in MySQLi

Question

I am trying to pass a string into my MySQLi prepared statement but it gives me the error:

Cannot pass parameter by reference in MySQLi

Here is the relevant code:

$kv = json_encode(array($key => $value));
$stmt->prepare("insert into rules (application_id, ruletype, rule_name, rule_info) values (?, ?, ?, ?);");
$stmt->bind_param('iiss', $application_id, 1, $config_name, $kv);

Solution

'1' cannot be passed by reference because it's not a variable but a literal. You need to create a variable with mentioned value and bind it instead because bind_param() function expects variables passed by reference.

Comments

[Marc B]

Why not simply embed the '1' directly into the query? If it's a static value, there's no point in making it a bound parameter. Otherwise, simply do $one = 1; and then pass in $one into the bind call. You can't make a reference to a constant.

[jeroen]

Note that the first string is not a parameter, those are the Type specification chars, see php.net/manual/en/mysqli-stmt.bind-param.php

[N.B.]

Yes, you're right, my bad - I skimmed trough the question and noticed that OP isn't passing an argument as variable. I'll edit the answer with your input.