PHP - Calling Child Method From Parent

I have these two classes:
Code: [Select]
<?php
class A {
private $id;
public function __construct() {
$this->id = '11111';
}
public function getProperty($prop) {
return $this->$prop;
}
}?>
Code: [Select]
<?php
class B extends A {
private $message = "Nope, can't see it";
public function __construct() {
parent::__construct();
$this->message = "Yep, I can see it";
}
}?>
I tried this, but it just outputs the id (the first call)
Code: [Select]
$class = new B;
echo $class->getProperty('id');
echo $class->getProperty('message');
Why is that? I thought I could use a parent method on a child property..


*EDIT* Using a public or protected visibility on the message property gets me the output I expect...how come?

Hi I am trying to create a hierarchy array from our mysql database.

What i have so far is:

//instantiate DB & connect
$database = new Database();
$db = $database->connect();

//instantiate question object

$question = new Question($db);

//query
    $results = $question->read(); 
   
      //check for data
    if ($results) {

     $question_arr['questions'] = array();
     $child_arr = array();
     
    while ($row = $results->fetch(PDO::FETCH_ASSOC)) {
        
        array_push($question_arr['questions'], $row);

        $question_arr['questions'][] = buildTree($row);

    }
        print_r($question_arr['questions']);
} else {
    echo json_encode(array('message'=>'nothing here!.'));
}


function buildTree($child) {
    $branch = array();
   foreach ($child as $row) {
    
    $childresults = $question->read_children($row['parentid']); 
    
           while ($childrow =$childresults->fetch(PDO::FETCH_ASSOC)) {
             
            $children = buildTree($childrow);

            if ($children) {
             $row['children'] = $children;
            }
         
            $branch[] = $childrow;
        }
    }
   //}
    return $branch;
}

in my Questions.php file:

<?php
class Question{
    private $conn;
    public $id;
    public $childid;
    public $parentid;
    public $question;
    public $pageid;
    public $numclicks;
    public $typeid;
    public $date_created;

 
     // Constructor with DB
     public function __construct($db) {
        $this->conn = $db;
      }

   public function read() {
        //create query(sql statement)
      $query = 'SELECT id as parentid, question, pageid, typeid,numclicks,date_created from ct_questions';
      // Prepare statement
      $stmt =$this->conn->prepare($query);
      // Execute query
      $stmt->execute();
      return $stmt;
    }

public function read_children($parentid)
{
//This is from a View I created in Mysql
    $query = 'SELECT parent_question, parentid, parent_pageid, child_question, childid, child_pageid from ct_vquestion_parent_child_lookup where parentid='.$parentid.'';
    // Prepare statement
    $stmt = $this->conn->prepare($query);
  
    // Execute query
    $stmt->execute();
   
    return $stmt;
}
}

 

the current errors i am getting a

<br /> <b>Notice</b>: Undefined variable: question in <b>C:\htdocs\api\questions\read.php</b> on line <b>41</b><br /> <br /> <b>Fatal error</b>: Uncaught Error: Call to a member function read_children() on null in C:\htdocs\api\questions\read.php:41 Stack trace: #0 C:\htdocs\api\questions\read.php(28): buildTree(Array) #1 {main} thrown in <b>C:\htdocs\api\questions\read.php</b> on line <b>41</b><br />

 

My script has 3 classes (that are relevant to this discussion): DB, User and Validate. They are all in independent files and loaded automatically, when required, by an autoloader.
Both the User class and the Validate class have a private variable $_db which is instantiated by their class constructor: $this->_db = DB::getInstance();
At the top of the script I declare new instances: $user = new User(); and $validate = new Validate();
I then call a method in $user: $found = $user->findInUsers ( .... )
From within the findInUsers method I then want to call the query method in the DB class. My problem is that I can't find a way to do this that works.
I have tried $this->_db->query( ... ), $_db->query( ... ), but neither works.

The error messages I am getting a
An error occurred in script '/srv/http/classes/User.php' on line 42: Undefined variable $_db
Uncaught Error: Call to a member function query() on null in /srv/http/classes/User.php:42

Any pointers as to what I am doing wrong, or what I should be doing, would be most welcome.

I have one table but i try to make like the result not finished. Hmm.. can you see my table :  FireShot Screen Capture #003 - 'localhost _ 127_0_0_1 _ pmis_dbase _ rekening_kegiatan I phpMyAdmin 4_0_4_1' - localhost_phpmyadmin_index_php_db=pmis_dbase&table=rekening_kegiatan&target=sql_php&token=93960ef7b5.png   803.36KB   0 downloads I want to declare sum for parent kd_rekening in same row for "Anggaran" => jns_anggaran =1 and "Perubahan" => jns_anggaran = 2. And child ust load field nilai.
 Untitled.jpg   34.7KB   0 downloads   Thanks before

Hello.

i have some code that works with out using parent and child but i dont think im doing it in the correct oop way. would someone maybe please just have a little look for me please.

by the way.. i know im not ment to use global but thats how i was shown to do that on my tutorial videos.. i'll address that in another post

so.
in this example i have this pages class
Code: [Select]
<?PHP
require_once(LIB_PATH.DS.'database.php');

class Pages {



protected static $table_name="pages";

protected static $db_fields = array(
'id',
'pageName',
'contTemp_id',
'contElements_id',
  'title',
'sub_title',
'description',
'about',
'image',
'created',
'dateMod',
'timeMod');


public $id;
public $pageName;
public $contTemp_id;
public $contElements_id;
public $title;
public $sub_title;
public $description;
public $about;
public $image;
public $created;
public $dateMod;
public $timeMod;



// "new" is a reserved word so we use "make"(or "build")
public static function make(

$id="",
$pageName="",
$contTemp_id="",
$contElements_id="",
  $title="",
$sub_title="",
$description="",
$about="",
$image="",
$created="",
$dateMod="",
$timeMod="") {

if(!empty($title)) {

$kw = new NavL3();
$kw->id = (int)$id;
$kw->pageName = $pageName;
$kw->contTemp_id = (int)$contTemp_id;
$kw->contElements_id = (int)$contElements_id;
$kw->title = $title;
$kw->sub_title = $sub_title;
$kw->description = $description;
$kw->about = $about;
$kw->image = $image;
$kw->created = $created;
$kw->dateMod = $dateMod;
$kw->timeMod = $timeMod;

return $kw;
}else{
return false;
}
} //end function make


public static function find_by_pageName($id){
    global $database;

$sql = "SELECT * FROM ".self::$table_name." WHERE id='".$database->escape_value($id)."'";
$result_array = self::find_by_sql($sql);

return !empty($result_array) ? array_shift($result_array) : false;
}


public static function find_by_pageID($pageID=0){
global $database;
$sql = "SELECT * FROM ".self::$table_name." WHERE id=".$database->escape_value($pageID)." LIMIT 1";
$result_array = self::find_by_sql($sql);
return !empty($result_array) ? array_shift($result_array) : false;
}


// Common Database Methods
public static function find_all(){
global $database;
$sql = "SELECT * FROM ".self::$table_name."";
return self::find_by_sql($sql);
}

public static function find_by_id($id=0){
global $database;
$sql = "SELECT * FROM ".self::$table_name." WHERE id=".$database->escape_value($id)." LIMIT 1";
$result_array = self::find_by_sql($sql);
return !empty($result_array) ? array_shift($result_array) : false;
}

public static function find_by_sql($sql){
global $database;
$results_set = $database->query($sql);
$object_array = array();
while($row = $database->fetch_array($results_set)){
$object_array[] = self::instantiate($row);
}
return $object_array;
}

public static function count_all(){
global $database;
$sql = "SELECT COUNT(*) FROM ".self::$table_name;
$results_set = $database->query($sql);
$row = $database->fetch_array($results_set);
return array_shift($row);
}

public static function instantiate($result){
$object = new self;
foreach($result as $attribute => $value){
if($object->has_attribute($attribute)){
$object->$attribute = $value;
}
}
return $object;
}

private function has_attribute($attribute){
$object_vars = $this->attributes();
return array_key_exists($attribute, $object_vars);
}


protected function attributes(){
$attributes = array();
foreach(self::$db_fields as $field){
if(property_exists($this, $field)){
$attributes[$field] = $this->$field;
}
}
return $attributes;
}

protected function sanitized_attributes(){
global $database;
$clean_attributes = array();
foreach($this->attributes() as $key => $value){
$clean_attributes[$key] = $database->escape_value($value);
}
return $clean_attributes;
}

public function save(){
return !empty($this->id) ? $this->update() : $this->create();
}

public function create(){
global $database;
$attributes = $this->sanitized_attributes();
$sql = "INSERT INTO ".self::$table_name." (";
$sql .= join(", ", array_keys($attributes));
$sql .= ") VALUES ('";
$sql .= join("', '", array_values($attributes));
$sql .= "')";
if($database->query($sql)){
$this->id = $database->insert_id();
return true;
}else{
return false;
}
}

public function update(){
global $database;
$attributes = $this->sanitized_attributes();
$attribute_pairs = array();
foreach($attributes as $key => $value){
$attribute_pairs[] = "{$key}='{$value}'";
}
$sql = "UPDATE ".self::$table_name." SET ";
$sql .= join(", ", $attribute_pairs);
$sql .= " WHERE id=".$database->escape_value($this->id);
$database->query($sql);
return ($database->affected_rows() == 1) ? true : false;
}

public function delete(){
global $database;
$sql = "DELETE FROM ".self::$table_name." ";
$sql .= "WHERE id=".$database->escape_value($this->id);
$sql .= " LIMIT 1";
$database->query($sql);
return ($database->affected_rows() == 1) ? true : false;
}



} //end class blogs
?>



and i have this conttemp class
Code: [Select]
<?PHP
require_once(LIB_PATH.DS.'database.php');

class Conttemps {

protected static $table_name="contTemps";

protected static $db_fields = array(
'id',
'name',
'created',
'dateMod',
'timeMod');


public $id;
public $name;
public $created;
public $dateMod;
public $timeMod;



// "new" is a reserved word so we use "make"(or "build")
public static function make(

$id,
$name="",
$created="",
$dateMod="",
$timeMod="") {

if(!empty($name)) {

$kw = new Templates();
$kw->id = (int)$id;
$kw->name = $name;
$kw->created = $created;
$kw->dateMod = $dateMod;
$kw->timeMod = $timeMod;

return $kw;
}else{
return false;
}
} //end function make



public function find_contTemp($pageID){

$page = Pages::find_by_pageID($pageID);
$pageCID = $page->contTemp_id;

$sql = "SELECT * FROM ".self::$table_name." WHERE id=".$pageCID."";
$result_array = self::find_by_sql($sql);
return !empty($result_array) ? array_shift($result_array) : false;
}


// Common Database Methods
public static function find_all(){
global $database;
$sql = "SELECT * FROM ".self::$table_name."";
return self::find_by_sql($sql);
}

public static function find_by_id($id=0){
global $database;
$sql = "SELECT * FROM ".self::$table_name." WHERE id=".$database->escape_value($id)." LIMIT 1";
$result_array = self::find_by_sql($sql);
return !empty($result_array) ? array_shift($result_array) : false;
}

public static function find_by_sql($sql){
global $database;
$results_set = $database->query($sql);
$object_array = array();
while($row = $database->fetch_array($results_set)){
$object_array[] = self::instantiate($row);
}
return $object_array;
}

public static function count_all(){
global $database;
$sql = "SELECT COUNT(*) FROM ".self::$table_name;
$results_set = $database->query($sql);
$row = $database->fetch_array($results_set);
return array_shift($row);
}

public static function instantiate($result){
$object = new self;
foreach($result as $attribute => $value){
if($object->has_attribute($attribute)){
$object->$attribute = $value;
}
}
return $object;
}

private function has_attribute($attribute){
$object_vars = $this->attributes();
return array_key_exists($attribute, $object_vars);
}


protected function attributes(){
$attributes = array();
foreach(self::$db_fields as $field){
if(property_exists($this, $field)){
$attributes[$field] = $this->$field;
}
}
return $attributes;
}

protected function sanitized_attributes(){
global $database;
$clean_attributes = array();
foreach($this->attributes() as $key => $value){
$clean_attributes[$key] = $database->escape_value($value);
}
return $clean_attributes;
}

public function save(){
return !empty($this->id) ? $this->update() : $this->create();
}

public function create(){
global $database;
$attributes = $this->sanitized_attributes();
$sql = "INSERT INTO ".self::$table_name." (";
$sql .= join(", ", array_keys($attributes));
$sql .= ") VALUES ('";
$sql .= join("', '", array_values($attributes));
$sql .= "')";
if($database->query($sql)){
$this->id = $database->insert_id();
return true;
}else{
return false;
}
}

public function update(){
global $database;
$attributes = $this->sanitized_attributes();
$attribute_pairs = array();
foreach($attributes as $key => $value){
$attribute_pairs[] = "{$key}='{$value}'";
}
$sql = "UPDATE ".self::$table_name." SET ";
$sql .= join(", ", $attribute_pairs);
$sql .= " WHERE id=".$database->escape_value($this->id);
$database->query($sql);
return ($database->affected_rows() == 1) ? true : false;
}

public function delete(){
global $database;
$sql = "DELETE FROM ".self::$table_name." ";
$sql .= "WHERE id=".$database->escape_value($this->id);
$sql .= " LIMIT 1";
$database->query($sql);
return ($database->affected_rows() == 1) ? true : false;
}




} //end class blogs
?>


the bit im interested in is this function in the Conttemp class

Code: [Select]
public function find_contTemp($pageID){

$page = Pages::find_by_pageID($pageID);
$pageCID = $page->contTemp_id;

$sql = "SELECT * FROM ".self::$table_name." WHERE id=".$pageCID."";
$result_array = self::find_by_sql($sql);
return !empty($result_array) ? array_shift($result_array) : false;
}


it call a function in from the Pages class.

i could take the function from here and put it in the Pages class i guess but i was wondering about Exends.

should i do class Conttemps extends Pages {

and use something like

Code: [Select]
public function find_contTemp($pageID){

$pageCID= Pages::contTemp_id;


$sql = "SELECT * FROM ".self::$table_name." WHERE id=".$pageCID."";
$result_array = self::find_by_sql($sql);
return !empty($result_array) ? array_shift($result_array) : false;
}

i guess that wont work because its not getting the $pageID

but anyway..

any thoughts ????

thanks
rick