CODEWITHSUNDEEP
phpfunctioninheritance
NETFLOX
NETFLOX

Reputation: 119

Access to inherited function not possible in PHP

i try to illustrate articles about PHP and have built with this structure:

Article

-- ChildArticle

I now want to access a function in the ChildArticle class that is inherited from the Article class.

Here is my Article class:

<?php
namespace App\Article;
use PDO;
class Articles
{
private $id;
private $name;
private $cid;
private $ordernumber;
private $description;
private $descriptionLong;
private $childArticles;

/**
 * @return mixed
 */
public function getId()
{
    return $this->id;
}

/**
 * @return mixed
 */
public function getName()
{
    return $this->name;
}

/**
 * @return mixed
 */
public function getCid()
{
    return $this->cid;
}

/**
 * @return mixed
 */
public function getOrdernumber()
{
    return $this->ordernumber;
}

/**
 * @return mixed
 */
public function getDescription()
{
    return $this->description;
}
/**
 * @return mixed
 */
public function getDescriptionLong()
{
    return $this->descriptionLong;
}

/**
 * @return mixed
 */
public function getChildArticles()
{
    return $this->childArticles;
}

function readChildArticles(PDO $pdo){
   $stmt = $pdo->prepare(
        "SELECT articleID as id, ordernumber FROM `s_articles_details` WHERE ordernumber LIKE :ordernumberWOD AND ordernumber NOT LIKE :ordernumber"
    );
    $stmt->execute([
        'ordernumberWOD'=>$this->ordernumber.".%",
        'ordernumber'=>$this->ordernumber
    ]);
    $this->childArticles = $stmt->fetchAll(PDO::FETCH_CLASS,"App\\Article\\ChildArticle");

    }


}

Here is my ChildArticle class:

class ChildArticle extends Articles
{

}

Now I want to read the order numbers of the child articles:

    foreach ($article->getChildArticles() as $child){
        echo "Child: {$child->getOrdernumber()}<br>";
    }

My readChildArticles function:

function readChildArticles(PDO $pdo){
   $stmt = $pdo->prepare(
        "SELECT articleID as id, ordernumber FROM `s_articles_details` WHERE ordernumber LIKE :ordernumberWOD AND ordernumber NOT LIKE :ordernumber"
    );
    $stmt->execute([
        'ordernumberWOD'=>$this->ordernumber.".%",
        'ordernumber'=>$this->ordernumber
    ]);
    $this->childArticles = $stmt->fetchAll(PDO::FETCH_CLASS,"App\\Article\\ChildArticle");

}

My output is like:

Child: 
Child:
and so on

if i get the ordernumber via $child->ordernumber, it works.

Why doesn't my ChildArticle class take over the function exactly like the parameters?

And can you give me a hint how I can solve the problem or where I can read about it?

thx :)

Upvotes: 0

Views: 46

Answers (1)

deceze
deceze

Reputation: 522015

The problem is in the way PDO constructs the object: it creates an instance of the class (ChildArticle), then sets all the columns as properties on it. Since $ordernumber is private, this creates a separate property in each class, i.e. Article::$ordernumber and ChildArticle::$ordernumber are two entirely separate properties. The method in Article tries to access Article::$ordernumber.

Make the property at least protected, or change the way in which you instantiate the class.

If you don't have a good reason for using separate properties and getters, you may as well consider making the property public and getting rid of the getter method.

Upvotes: 1

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