Trying to get property of non-object using php oops concept - php

Question

I am trying to retrieve the data from database using OO-PHP
Here is my code
user.php
<?php
require_once("init.php");
class User{
public $id;
public $username;
public $password;
public $first_name;
public $last_name;
public static function find_all_users(){
return self::find_this_query("SELECT * FROM users");
}
public static function find_user_by_id($user_id){
global $database;
/* $result_set = $database->query("SELECT * FROM users WHERE id=$user_id LIMIT 1");*/
$result_set = self::find_this_query("SELECT * FROM users WHERE id=$user_id LIMIT 1");
$found_user = mysqli_fetch_array($result_set);
return $found_user;
}
public static function find_this_query($sql){
global $database;
$result_set = $database->query($sql);
$the_object_array = array();
while($row = mysqli_fetch_array($result_set)){
$the_object_array[] = self::instantation($row);
}
return $result_set;
}
public static function instantation($the_record){
$the_object = new self;
/* $the_object->id = $found_user['id'];
$the_object->username = $found_user['username'];
$the_object->password = $found_user['password'];
$the_object->first_name = $found_user['first_name'];
$the_object->last_name = $found_user['last_name'];*/
foreach($the_record as $the_attribute => $value){
if($the_object->has_the_attribute($the_attribute)){
$the_object->$the_attribute = $value;
}
}
return $the_object;
}
private function has_the_attribute($the_attribute){
$object_properties = get_object_vars($this);
return array_key_exists($the_attribute, $object_properties);
}
}
?>
database.php
public function query($sql){
/*$result = mysqli_query($this->connection,$sql);*/
$result = $this->connection->query($sql);
$this->confirm_query($result);
return $result;
}
index.php
$users = User::find_all_users();
foreach($users as $user){
echo $user->username;
}
When trying to retrieve the users from the database I get the error
Trying to get property of non-object

Answer 1

The problem is, you are not returning the users array from this method
public static function find_this_query($sql){
global $database;
$result_set = $database->query($sql);
$the_object_array = array();
while($row = mysqli_fetch_array($result_set)){
$the_object_array[] = self::instantation($row);
}
return $result_set;
}
instead you should return the array as
public static function find_this_query($sql){
global $database;
$result_set = $database->query($sql);
$the_object_array = array();
while($row = mysqli_fetch_array($result_set)){
$the_object_array[] = self::instantation($row);
}
return $the_object_array;
}
and just in case the result is empty, check for it as
$users = User::find_all_users();
if($users != null){
foreach($users as $user){
echo $user->username;
}
}