PHP to loop records from class method - php

Question

I got below class to fetch records in database, how can use foreach to loop all data in page?
class User{
public function get_user_listing($user_id, $mysqli){
$sql = $mysqli->query("SELECT * FROM `listing` WHERE user_id='".$user_id."'");
if($sql->num_rows > 0){
return $query->result();
}else{
return false;
}
}
}
in my page, if I call:
$user = new User;
$listing = $user->get_user_listing($user_id, $mysqli);
foreach(listing as $value){
echo $value->table_field;
}
But I think that is not a correct way.

Answer 1

You need to return the actual result $sql:
if($sql->num_rows > 0){
return $sql;
} else {
return false;
}
Since you are returning a result set you need to fetch rows:
$user = new User;
$listing = $user->get_user_listing($user_id, $mysqli);
while($row = $listing->fetch_object()){
echo $row->table_field;
}
Or you could add the fetch loop to the class function and return an array of $row[] objects.
Also, I would make some changes here:
private $mysqli;
public function __construct($mysqli) {
$this->mysqli = $mysqli;
}
public function get_user_listing($user_id) {
$mysqli = $this->mysqli;
//or just use $sql = $this->mysqli->query("SELECT * FROM `listing` WHERE `user_id` = '$user_id'");
//etc...
}
Then:
$user = new User($mysqli);
$listing = $user->get_user_listing($user_id);

Answer 2

Better use a prepared statement to protect from SQL injection. And check the returned value from get_user_listing for false or undef.
public function get_user_listing($user_id, $mysqli){
$sql = "SELECT * FROM `listing` WHERE user_id=?";
if ($stmt = $conn->prepare($sql)) {
$stmt->bind_param("i", $user_id);
$stmt->execute();
$result = $stmt->get_result();
return $result;
}
}
$user = new User;
$result = $user->get_user_listing($user_id, $mysqli);
if(isset($result))
{
while ($row = $result->fetch_assoc()) {
print $row['table_field'];
}
/* free result set */
$result->free();
}