PHP PDO prepared delete statement with MySQL fails inside Ajax call [duplicate] - php

Question

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When to use single quotes, double quotes, and backticks in MySQL
(13 answers)
Closed 7 years ago.
I have a failing PDO Prepared DELETE statement inside a PHP file called with AJAX.
My AJAX call looks like this:
var data = {action: "deleteTask", value: "1"};
$.ajax({
type: "POST",
dataType: "json",
url: "ajax.php",
data: data,
success: function(data) {
alert(data);
},
error: function() {
alert("Something's wrong!");
}
});
My ajax.php looks like this:
<?php
...
function delete(){
$return = "something must be right...";
require('connect.php');
$sql = "DELETE FROM 'tasks' WHERE 'task_id' = ?";
$stmt = $dbcon->prepare($sql);
$stmt->execute(array($_POST["value"]));
$return["json"] = json_encode($return);
echo json_encode($return);
}
?>
Here is a sample of connect.php:
<?php
// Configuration
$username = 'me';
$password = '1234';
$server = 'localhost';
$database = 'mydb';
try {
$dbcon = new PDO("mysql:host=$server;dbname=$database",$username,$password);
$dbcon->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch(PDOException $er) {
echo 'ERROR: ' . $er->getMessage();
}
?>
A few things that I have already established:
1) My ajax call works fine if I comment out everything related to the PDO statement;
2) My connect.php file works, because I have tested it with standard HTML forms (as opposed to calling it from ajax);
3) there are no typos in the names of the table and the field of the DB;
4) The $_POST["value"] gives the the right value corresponding to the record I am trying to delete.
5) When I set brakepoints on each line related to the PDO, when I am at the line: $stmt->execute(array($_POST["value"])); and I click "Step Into", it jumps straight to the alert("Something's wrong!"); in the Ajax (nothing gets executed in the ajax.php after that line)
I have spent many hours trying to figure out what is wrong with this and read all the posts that exist on the subject, but my problem seems particular, so any help would be much appreciated! Thanks.

Answer 1

You should look into the browser's the Net responce. It should show a SQL error. If you use MySQL your query should look:
DELETE FROM `tasks` WHERE `task_id` = ?
And if it is PostgreSQL:
DELETE FROM "tasks" WHERE "task_id" = ?

Answer 2

Seems like you forgot to add the code:
delete();
Once you will add it, you will actually call the function and not only declare it.
Another option, try and set PDO to print error. http://php.net/manual/en/pdo.errorinfo.php Then you will the error printed back in the console.