php: Database Class with PDO. How can i make it better? - php

Question

So I started to get a little more practice in php and want to create a object oriented forum. Therefor I want to have a Database class such like:
<?php
class Database {
public $databaseConnection;
function __construct(){
$this->databaseConnection = new PDO('sqlite:test.sq3', 0, 0);
$this->databaseConnection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$params = NULL;
$pdoStatement = $this->databaseConnection->prepare('CREATE TABLE IF NOT EXISTS user(
id INTEGER PRIMARY KEY,
username VARCHAR(40) NOT NULL UNIQUE,
numberoflogins INTEGER DEFAULT 0,
bannedstatus BOOLEAN DEFAULT FALSE,
dateofjoining TIME
)');
$pdoStatement->execute(array_values((array) $params));
}
function query($sql, $params = NULL){
$s = $this->databaseConnection->prepare($sql);
$s->execute(array_values((array) $params));
return $s;
}
function insert($table, $data){
self::query("INSERT INTO $table(" . join(',', array_keys($data)) . ')VALUES('. str_repeat('?,', count($data)-1). '?)', $data);
return $this->databaseConnection->lastInsertId();
}
}
Then I do this in the same script:
$database = new Database();
$database->insert('user',array( 'id' => 0,
'username' => 'gulaschsuppe',
'numberoflogins' => 23,
'bannedstatus' => TRUE,
'dateofjoining' => time()));
$searchID = 0;
$userData = $database->query('SELECT username FROM user WHERE id = 0');
$username = $userData->fetchAll();
print_r(array_values($username));
?>
I just wanted to see how things working. The most important part of the code is the class. I needed a little bit time to figure out how I get the information I wanted. This is what I get.
Array ( [0] => Array ( [username] => gulaschsuppe [0] => gulaschsuppe ) )
Everythings working, but I don´t think this is best way to get the informations. I get an Array with an Array. Also, now there is no validation but first I want to focus on the functions query and insert.
So, can you explain how the last part with username => g. [0] => g. occured ?
I would like to know how I can improve the functions and please tell me when I do something totally wrong.

Answer 1

Array (
[0] => Array (
[username] => gulaschsuppe
[0] => gulaschsuppe
)
)
You're getting the result with both names columns (so you could do $row['username']) and numerically (so you can do $row[0]). This is the default PDO behavior. You need to use the PDO::FETCH_* constants in order to change the fetched results. PDO::FETCH_BOTH is the default value.
You can either set it when you're fetching:
$username = $userData->fetchAll(PDO::FETCH_ASSOC);
Or globally at some point:
$this->databaseConnection->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
In the case that you want only a single column, you can use this fetch mode:
$usernames = $userData->fetchAll(PDO::FETCH_COLUMN);
// $usernames = array('gulaschsuppe');
This fetches only a single column for each row, without wrapping each result in another array (column 0 is fetched by default).
See the PDOStatement::fetch() documentation for more details.