UPDATE MYSQL DATA ROW USING IF ELSE WITHIN FOR LOOP - php

Question

I am trying to make the user send an email which is not already referred to by him with below code. But else statement updates e-mail to data even if there is already the same e-mail existing in MySQL data row.
if(isset($row)){
if (array_key_exists("email", $_POST)){
$query = "SELECT id FROM users WHERE email = '".mysqli_real_escape_string($link,$_POST['email'])."' LIMIT 1";
$ans = mysqli_query($link, $query);
if(mysqli_num_rows($ans) > 0){
$nofriend = $_POST['email']." is already registered.";
}
else{
$referredemails = $row["rfremails"];
$array = explode(",", $referredemails);
print_r($array);
for($i = 0; $i < sizeof($array); $i++){
if($array[$i] == $_POST["email"]){
$nofriend = "This e-mail is already referred by you.";
}
else{
$referdate = getdate();
$timestamp = "$referdate[mday] $referdate[month] $referdate[year]";
$opngems = $row["gems"];
$query = "UPDATE users SET rfremails = '".$referredemails.",".$_POST["email"]."', gems = '".$opngems."+1-".$timestamp."-".$_POST["email"]."' WHERE id = '".mysqli_real_escape_string($link,$_SESSION['id'])."' LIMIT 1";
mysqli_query($link,$query);
header("Location: showupdate.php");
}
}
}
}
}

Answer 1

it is caused by condition in for cycle
for($i = 0; $i < sizeof($array); $i++){
if($array[$i] == $_POST["email"]){
//stuff
} else {
//....$query = "UPDATE users SET rfremails =...
}
}
when user have referred more than one email this condition will be evaluated as false and thus else segment of code will be processed, resulting in update in database.
it is wise to use help variables for such cases as this. e.g.:
$noFriend = false;
for ($i = 0; $i < sizeof($array); $i++) {
if ($array[$i] == $_POST["email"]) {
$noFriend = true;
...
}
if ($noFriend === false) {
//update
}
you can also use break statement when you find first occurence of same referred email, to speed things up.