多个插件无法使用mysql

Question

I'm trying to insert six records in a table, but when the script runs I get the following

error: 'Fatal error: Cannot pass parameter by reference'.

See the code below for the specific line:

$ySQL = "SELECT ID_USUARIO FROM USUARIOS WHERE EMAIL=?";
$stmt = $oConni->prepare($ySQL) or die($oConni->error);
$stmt->bind_param('s', $datos[8]);
$stmt->execute();
$stmt->store_result();
$stmt->bind_result($idUsuario);
$stmt->fetch();
$stmt->close();

for($i=1;$i<7;$i++){
   $vSQL = "INSERT INTO PERMISOS (ID_USUARIO,ID_ACCION,PERMISOS) VALUES(?,?,?)";
   $stmt = $oConni->prepare($vSQL) or die($oConni->error);

   // ERROR. The following line throws it:
   $stmt->bind_param('iis', $idUsuario, $i, 'S');
   $stmt->execute();
   $stmt->store_result();
   $stmt->close();
}

Answer 1

Here is mysqli_stmt::bind_param()'s signature:

bool mysqli_stmt::bind_param ( string $types , mixed &$var1 [, mixed &$... ] )

As you can see, the method accepts all parameters – except the first one – as references.

You need at least a variable or a function's return value for having a reference. You cannot use a String Literal like 'S'.

Here is a fix:

$str = 'S';
$stmt->bind_param('iis', $idUsuario, $i, $str);