Using a database class in my user class

Question

In my project I have a database class that I use to handle all the MySQL stuff. It connects to a database, runs queries, catches errors and closes the connection.

Now I

Answer 1

What I like to do is make the database class with the Singleton pattern in mind. That way, if you already have a database object, it just retrieves it, otherwise creates a new one. For example:

Database.class.php

class Db
{
    protected static $_link;

    private function __construct()
    {
        // access your database here, establish link
    }

    public static function getLink()
    {
        if(self::_link === null) {
            new Db();
        }
        return self::_link;
    }

    // etc.

}


User.class.php

class User
{
    protected $_link;    // This will be the database object
    ...

    public function __construct()
    {
        $this->_link = Db::getLink();
    }

}

And now you can use User's $_link property to do the database functions, like $this->_link->query(...). You don't necessarily have to put the Db::getLink() in the constructor if your class doesn't have to interact with the database that much.