What is the correct way to access a database handle in a child class in PHP?

When working with database connections in PHP, it is important to ensure that database handles are properly accessed in child classes that inherit from a parent class. To access a database handle in a child class, you can pass the database handle as a parameter to the child class constructor or set it as a property of the child class. This allows the child class to use the database handle without needing to create a new connection. 

<?php
class ParentClass {
    protected $db;

    public function __construct($db) {
        $this->db = $db;
    }
}

class ChildClass extends ParentClass {
    public function __construct($db) {
        parent::__construct($db);
    }

    public function fetchData() {
        // Use $this->db to access the database handle
        $result = $this->db->query("SELECT * FROM table");
        // Process the query result
    }
}

// Create a database connection
$db = new PDO("mysql:host=localhost;dbname=myDB", "username", "password");

// Pass the database handle to the child class
$child = new ChildClass($db);

// Access the database handle in the child class
$child->fetchData();
?>

Keywords

database handle child class PHP access correct way

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