在为PDO绑定参数之后构建响应数组

Question

I am trying to build the array that will return to my ajax success. How do I build the array after binding it to something like :some variable.

The following script runs to completion, and inserts with no problem into sql. But the variables comment and transaction come back as null in the response. I think the problem is using $comment and $transaction when building the array. What is the right way to reference these values in the array?

        require('../dbcon2.php');
        //Connection 1
        try {
          $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
          $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
          $stmt = $conn->prepare("UPDATE listings SET comment = :comment, transaction = :transaction, ad_link = :ad_link WHERE id = :id");
            // Bind
            $stmt->bindParam(':id', $_POST['id']);
            $stmt->bindParam(':comment', $_POST['comment']);
            $stmt->bindParam(':transaction', $_POST['transaction']);
          $stmt->execute();
          // Build array
           $response = array
                 ('state'  => 200, "success" => true, "id" => ':id', "comment" => $comment, "transaction" => $transaction 
                 );
          exit(json_encode($response));

        }
    catch (Exception $e) {
                // create a asociative array
                $data = array("success" => false, "sentence" => $sql, "error" => $e.getMessage());
                // encode data and exit.
                exit(json_encode($data));
            }

Answer 1

As per OP's wish:

Do as you did for "id" => ':id'

"id" => ':id', "comment" => ':comment', "transaction" => ':transaction'

Plus, quoting Jeroen (kudos to)

Why don't you use the $_POST variable? That contains the values you need and you use them already in your database query.

Answer 2

You can't retrieve bound values after calling ->bindParam() ; also, the variables $comment and $transaction aren't defined (unless you set them yourself or when using voodoo php settings).

That said, you already know those values:

$response = array(
   'state'        => 200, 
    "success"     => true, 
    "id"          => $_POST['id'], 
    "comment"     => $_POST['comment'], 
    "transaction" => $_POST['transaction'], 
);

Btw, in the exception branch you have a small bug:

$data = array("success" => false, "sentence" => $sql, "error" => $e.getMessage());
                                                                   ^

You should use $e->getMessage() instead.