使用mysqli的类

Question

I am building an API in PHP and I have a question. I'm using classes, and some of these classes need to access my database. However, I don't want to define variables for the database in every single class in order to open it, or have to send my mysqli object as a parameter of every single class constructor.

What would be the best way to go about this? Do I define a global variable of some kind?

Answer 1

A classic solution would be as follows

1. Create an instance of dbatabase handler class, either raw mysqli (worse) or better abstraction class (way better)
2. In the constructor of your application class take this db class instance as a parameter and assign it to a local variable
3. Use this variable with your class.

A quick example:

class Foo()
{
    protected $db;
    function __construct($db);
    {
        $this->db = $db;
    }
    function getBar($id)
    {
        return $this->db->getOne("SELECT * FROM bar WHERE id=?i", $id);
    }
}
$db = new safeMysql();
$foo = new Foo($db);
$bar = $foo->getBar($_GET['id']);