Question

Can someone tell me when you prepare() a statement (in my case an update statement) and then execute() it, I then check using rowCount() after the update query (see code below) if rowCount() > 0 if it is then a match was found and update took place, but I then got an else statement.

To make sure I am not confusing myself with syntax errors and conditions in statements, I want to ask in my code below (have commented specific area in detail) does the else statement basically mean cannot update because a match was not found and/or a possible syntax error or some other error? I think it means what I put in bold just want to ensure I am not confusing myself.

Please ignore the SQL UPDATE syntax itself in the prepare statement as it’s wrong and will deal with later. I think the code explains better along with a detailed comment in area I am talking about.

// check if key is set and alphanumeric and equals 40 chars long
// we use sha1 so it will always be 40 chars long.
if(isset($_GET['key']) && ctype_alnum($_GET['key']) && strlen($_GET['key']) == 40){
$key = trim($_GET['key']);
}

// if key isset and valid
if(isset($key)){


try {
    // connect to database
    $dbh = sql_con();

    // checke if activation key matches and user_uid matches
    $stmt = $dbh->prepare("
            SELECT
              users_status.user_uid,
              users_status.user_activation_key
            FROM
              users_status
            JOIN
              users
            ON
              users_status.user_activation_key = ?
            AND
              users_status.user_uid = users.user_uid LIMIT 1");

    // execute query
    $stmt->execute(array($key));

    // if row count greater than 0 then match found
    if ( $stmt->rowCount() > 0 ) {

        // user verified; we now must update users status in users table to active = 1
        // and set the user_activation_key in the users_status to NULL
        $stmt = $dbh->prepare("
            UPDATE
              users.user_status,
              users_status.user_activation_key
            SET
              user_status = ".USER_STATUS_ACTIVE.",
              user_activation_key = NULL
            JOIN
              users
            ON
              users_status.user_activation_key = ?
            AND
              users_status.user_uid = users.user_uid LIMIT 1");

        // execute query
        $stmt->execute(array($key));

        if ( $stmt->rowCount() > 0 ) {

            echo 'account now activated';
            exit;

        } else {
            // update not sucessful
            // THIS IS THE BIT IM CONFUSED WITH;
            // IF RETURNED RESULT IS 0 (WHICH IT WILL BE IF I GET HERE WHEN RUNNING SCRIPT)
            // THEN I GUESS THAT MEANS THERE WAS NOT AN ERROR IN SQL SYNTAX BUT
            // CONDITION IN SQL STATEMENT COULD NOT BE MATCHED ? IS THAT CORRECT WHAT I AM THINKING ?
            // IF I AM CORRECT THEN OBVIOUSLY I WILL DISPLAY A MESSAGE TO USER AND EXIT HERE;
            // AS IF I AM THINKING RITE ANY SYNTAX ERROR WOULD BE CAUGHT BY CATCH BLOCK AND THIS ELSE STATEMENT
            // MEANS COULD NOT UPDATE BECAUSE NO MATCH IN UPDATE QUERY COULD BE FOUND ?
        }


    } // else no match found
    else {

        // no match found invalid key
        echo '<h1>Invalid Activation Link</h1>';

        $SiteErrorMessages =
        "Oops! Your account could not be activated. Please recheck the link in your email.
        The activation link could not be found or the account has already been activated.";

        SiteErrorMessages();

        include($footer_inc);
        exit;

    }

    // close database connection
    $dbh = null;

} // if any errors found log them and display friendly message
catch (PDOException $e) {
    ExceptionErrorHandler($e);
    require_once($footer_inc);
    exit;
}

} else {

// else key not valid or set
echo '<h1>Invalid Activation Link</h1>';

$SiteErrorMessages =
"Oops! Your account could not be activated. Please recheck the link in your email.
The activation link appears to be invalid.<br /><br />
If the problem persists please request a new one <a href='/member/resend-activation-email'>here</a>.";

SiteErrorMessages();

include($footer_inc);
exit;

}

Answer 1

You are right:

if $stmt->rowCount() == 0

Then it means no rows has been updated.

If you heve sql errors or errors while executing query you receive a FALSE return value or also a PDO EXCEPTION when you execute

  execute(array($key));