Trouble dealing with results from a SELECT query with MySQLI - php

Question

The basic control structure I'm trying to get to work is to query the DB with the username and email, both of which are unique keys, and if either are in the DB let the user know that they have been taken and to please pick something else. The problem I'm running into is getting the result data in a usable form that I can then check the user-supplied data against.
I cut out the prepared statements for insertion from the snippit, as well as the validation routines, since both of them are working fine.
DB connection snippit
try {
if(!($dbc = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME))){ // Creates the $dbc variable object so we can
// have a connection to the database.
// uses mysqli functions.
throw new Exception;
}
}
catch (Exception $e) {
echo '<p>Could not connect to the database. Please contact the system administrator.</p>';
}
Snippit of Registration script
//before this was validation routines, if anything was wrong the script generated something into $reg_errors which is an array.
if(empty($reg_errors))
{
//queries database if there are any matches for username or email from user input.
if($stmt = $dbc->prepare("SELECT `email`, `username` FROM `users` WHERE `email` = ? OR `username` = ?"))
{
$stmt->bind_param("ss", $e, $u);
$stmt->execute();
$stmt->store_result();
$rows = $stmt->num_rows; //gives the number of rows returned from SELECT query. 0 means no dupes, 1 means one record has BOTH email and username, 2 means two different records (one with email, one with username)
##THIS IS WHERE I'M RUNNING INTO TROUBLE GETTING THE DATA IN A USABLE FORM##
$stmt->close();
} else {
echo "<p>Can't talk to database right now. Try again later, please.</p>";
}
if($rows==0) //no dupes of username or email, so let's try and add them into the DB
{
//prepared statement for insertion into DB
//also get's the count of affected rows. 1 means record inserted correctly.
//asks DB if a new row was created, and if so, thanks user for
//registration on the site & sends an email to their email.
//if query doesnt work, an error is triggered
if($count==1) {
//constructs a thank you note and emails it to the user, using the email they supplied.
exit();
} else {
echo "<p>Unable to process your registration at this time. Please try again later..</p>";
}
} else { // both username and email might be already used in DB, and error msgs are generated for array.
if($rows==2) { // this checks to make sure both entries are dupes
$reg_errors['email'] = 'This email address has already been registered. If you have forgotten your password, use the link to the right to have your password sent to you.';
$reg_errors['username'] = 'This username has already been registered. Please try another.';
} else { //this checks to see which of the two (email or username) is already in DB if both arent dupes.
if((__NEED SOMETHING HERE FROM DB QUERY___ == $_POST['email']) && (__NEED SOMETHING HERE FROM DB QUERY___ == $_POST['username'])) { //both match entries in DB
$reg_errors['email'] = 'This email address has already been registered. If you have forgotten your password, use the link to the right to have your password sent to you.';
$reg_errors['username'] = 'This username has already been registered with this email address. If you have forgotten your password, use the link to the right to have your password sent to you.';
} elseif(__NEED SOMETHING HERE FROM DB QUERY___==$_POST['email']) { // email match
$reg_errors['email'] = 'This email address has already been registered. If you have forgotten your password, use the link to the right to have your password sent to you.';
} elseif(__NEED SOMETHING HERE FROM DB QUERY___==$_POST['username']) { // username match
$reg_errors['username'] = 'This username has already been registered. Please try another one.';
}
} // end of $rows==2 ELSE
} // end of $rows == 0 IF
} else { // end of empty reg_errors conditional
//do something if the reg_error array isnt empty..
}
i'm pretty sure the answer lies in iterations and using meta_data from the result mysqli object, but after beating my head against a wall for a couple days and pouring over the mysqli php manual pages like a maniac, I'm still no closer to figuring out what I should be doing. Could anyone point me in the correct direction?

Answer 1

Starting from the registration script, have you tried this:
if($stmt = $dbc->prepare("SELECT `email`, `username` FROM `users` WHERE `email` = ? OR `username` = ?"))
{
$stmt->bind_param("ss", $e, $u);
$stmt->execute();
$stmt->bind_result($email, $username);
$rows = $stmt->num_rows;
//Move Conditionals Up a Little
if( $rows == 0 ) { //If No Records are Found
//Continue Registration
}
else if( $rows == 1 ) { //If One Record is Found
$stmt->fetch();
//Do Something With $email and $username from DB Here
}
else { //If More than One Record is Found
while( $stmt->fetch() ) { //Iterate Through Records
//Do Something With $email and $username from DB Here
}
}
}