How can I retrieve the number of rows deleted with PDO?

Question

Hello everyone,

Okay, so I have been using a PDO wrapper for a project I'm working on, and I'm trying to find out whether a DELETE query was successful or not. Here is the code I am using:

/**
* A pretty straight-forward query to delete a row from the verification
* table where user_id is $user_id and code is $code
*/
$result = $this->database->query("DELETE FROM verification " .
                                 "WHERE user_id = %u AND code = %s",
                                 $user_id,
                                 $code);

/**
 * This function will grab the PDO's exec() return, which should
 * return the number of rows modified.
 */
if($this->database->getNumAffected($result) > 0)
    return true;
else
    return false;

The problem is, whether the DELETE query actually deletes a row or not, $this->database->getNumAffected($result) always returns '0'.

You can check out the wrapper, but basically $this->database->getNumAffected($result) simply returns exactly the same value PDO::exec() would return.

I tried this code without the wrapper (directly into PDO,) and I had the same problem but reverse: it always returned '1' (whether a row was deleted or not.)

Any help would be greatly appreciated.

EDIT: Based on this SO question, I'm doing everything right... I don't understand why this isn't working.

Answer 1

$query = $this->database->prepare("DELETE FROM verification WHERE user_id = :user_id AND code = :code", array('user_id' => $user_id, 'code' => $code));
$query->execute();

if ($query->rowCount() > 0) {
  return TRUE;
}
return FALSE;

Answer 2

It doesn't work as you expect because the 'wrapper' that you're using doesn't ever use PDO::exec() - it wraps everything in a PDO statement. According to a quick read of the source code for version 2.2.6 of the 'database' class from the URL you provided, the 'query' method should return an array which contains the statement handle:

502 $statement = $this -> getDatabaseConnection () -> prepare ( $query );
...
587 $ret = array ( $statement, func_get_args (), $lastIndex );
588     
589 return ( $ret );

So, assuming your $this->database->query() is calling this database class' query method, you should be able to do $result[0]->rowCount().

Note that your assertion to the earlier response that "the wrapper that [you are] using uses a different version of rowCount() because of an error that exists with the rowCount() function" is not true - the wrapper implements a numRows, but this is not the same thing as PDOStatement::rowCount(), which is intact inside of the statement handle returned from database::query().