How to make sure delete query removes a row?

Question

Here is my code:

$token   = $_GET['validate_activate']; // it's something like this "98j34f0j043f094f98325r"
$user_id = $_GET['user_id'];

// db connection here
$stmt = $dbh->prepare("DELETE FROM activate_token WHERE token = :token");
$stmt->execute(array(':token' => $token));

if ( /* deleting is success */ ) {
    // activating the user
} else {
    // your token is invalid
}

Well how can I make a correct condition for that if statement?

or use `select count` + `fetchColumn` – Kevin Jul 11 '16 at 23:05 — Kevin, Jul 11 '16 at 23:05

score 0 · Accepted Answer · answered Jul 11 '16 at 22:55

0

With the help of rowCount();

PDOStatement::rowCount() returns the number of rows affected by the last DELETE, INSERT, or UPDATE statement executed by the corresponding PDOStatement object.

if ( $stmt->rowCount() ) {
    // activating the user
} else {
    // your token is invalid
}

answered Jul 11 '16 at 22:55

e4c5

52,766
11
101
134

hello @Drew is there a bug in newer versions? Haven't used PHP for a couple of years – e4c5 Jul 11 '16 at 23:03
If it works on your deployment, and well tested, your method is what I would go with. It is just when you push your code around, it is dependent on the setup in action. From the manual: [not guaranteed](http://php.net/manual/en/pdostatement.rowcount.php) – Drew Jul 11 '16 at 23:04

score 0 · Answer 2 · answered Jul 11 '16 at 22:59

0

This should work, the pdo statement should return True or False if the delete query was successful

if($stmt->execute(array($token = $_GET['validate_activate']))) {
     // activating the user
} else {
    // your token is invalid
}

answered Jul 11 '16 at 22:59

Allen Butler

337
3
12

It can be successful and not remove a row. – Don't Panic Jul 11 '16 at 23:10
Assuming id is `unsigned` (0 or greater), `DELETE FROM table WHERE id = -1;` would return `true` – Will B. Jul 11 '16 at 23:10

score 0 · Answer 3 · answered Jul 11 '16 at 23:06

$stmt->execute returns a bool result, true if the sql query was successful so just use the result of that in your if statement:

$stmtWorked = $stmt->execute(array($token));
if ($stmtWorked) {
    // activating the user
} else {
    // your token is invalid
}

Also you can use mysqli_stmt_affected_rows() to count for many rows were deleted if you need to know a specific amount.

How to make sure delete query removes a row?

3 Answers3