PDO OOP Database

[skippt]

<?php
class Database {

public function __construct() {

}

public function connect() {
    /** CONNECTION **/
    $username = 'backstag_trythro';
    $password = 'mhagja150793mk';
    try {
        $dbh = new PDO('mysql:host=localhost;dbname=backstag_levtest', $username, $password);
    } catch (PDOException $e) {
        echo $e->getMessage();
    }

    /** UPDATE **/
    //PDO Class
    $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
    $dbh->setAttribute(PDO::ATTR_CASE, PDO::CASE_LOWER);

    $sth = $dbh->query("SELECT * FROM posts");
    $result = $sth->fetchAll(PDO::FETCH_OBJ);
    //print_r($result);
    $this->daa = $result[1]->title;
    }

}

I have a database class as seen above however I would like my code to have a different structure, like this:

<?php
class Database {

public function __construct() { }

public function connect() { }

public function select() { }

public function update() { }

public function delete() { }

}

So, everytime I call one of these functions I wouldn't have to repeat the connection code, instead I would call something like $this->connect();

I can't work out how to get variables to pass from one function to another within a class. When I split the code up, it has no trouble connecting but
I always get an error along the lines of "setAttribute undefined" or "query undefined". I think due to the connection not being passed to another function.

Is there an way I can do this?

[bradgrafelman]

Store the connection resource in a property and refer to that property within the methods (there's no "passing" involved - all methods have access to the object's properties).

[NogDog]

You could then have your constructor call the connect() method (in which case it could then be private), so that you don't have to explicitly call it from the client code, which might then look like:

$db = new Database();
$result = $db->select($args);