Select PHP PDO best way to make - php

Question

I have a question on how to draw a connection to a select box that is inside a function.
I call this way:
Function MySQL:
mysql.php
function conectar() {
try {
$dbh = new PDO("mysql:host=localhost;dbname=adm-new", 'root', '');
} catch (PDOException $dbe) {
echo $dbe->getMessage();
}
return $dbh;
}
$conn = conectar();
Function select:
menu.php
function z_menu_todos() {
global $conn;
$z_menu = "SELECT *
FROM z_menu
ORDER BY posicao ASC";
return $conn->prepare($z_menu);
}
I did not want to call the variable global $conn.
What would be the best way to do?

Answer 1

I would create a DatabaseFactory class which would serve for creating database connection, like this:
ConnectionFactory.php
class ConnectionFactory {
private $_connection;
public function __construct($dbName, $dbUser, $dbPassword, $dbHost = 'localhost'){
try {
$this->_connection = new PDO("mysql:host=$dbHost;dbname=$dbName", $dbUser, $dbPassword);
$this->_connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e){
throw new DatabaseFactoryException('Could not create connection:' . $e->getMessage());
}
}
public function getConnection(){
return $this->_connection;
}
}
After that I would create MenuRepository class which would server for executing queries associated with Menu, like this:
MenuRepository.php
class MenuRepository {
private $_connection;
public function __construct(PDO $connection){
$this->_connection = $connection;
}
public function getMenus(){
$stmt = $this->_connection->prepare("SELECT * FROM z_menu ORDER BY posicao ASC");
$stmt->execute();
return $stmt->fetchAll();
}
}
I would create configuration in separate file, like this:
config.php
define('DB_NAME', 'adm-new');
define('DB_USER', 'root');
define('DB_PASS', '');
After that I would use:
index.php
require __DIR__ . '/config.php';
require __DIR__ . '/ConnectionFactory.php';
require __DIR__ . '/MenuRepository.php';
$connectionFactory = new ConnectionFactory(DB_NAME, DB_USER, DB_PASS);
$connection = $connectionFactory->getConnection();
$menuRepository = new MenuRepository($connection);
$menus = $menuRepository->getMenus();

Answer 2

class Database
{
protected $conn;
public function __construct()
{
try {
$this->conn = new PDO("mysql:host=localhost;dbname=adm-new", 'root', '');
} catch (PDOException $dbe) {
echo $this->conn->getMessage();
}
}
public function z_menu_todos()
{
$z_menu = "SELECT *
FROM z_menu
ORDER BY posicao ASC";
return $this->conn->prepare($z_menu);
}
}
Usage
$database = new Database();
$stmt = $database->z_menu_todos();
Modify this as you require, this is a very basic example of how to do this, do not just copy and paste it.

Answer 3

In this case, you should avoid using global variables, because you can easily pass the connection to method as method argument, like this:
function conectar() {
try {
$dbh = new PDO("mysql:host=localhost;dbname=adm-new", 'root', '');
} catch (PDOException $dbe) {
echo $dbe->getMessage();
}
return $dbh;
}
$conn = conectar();
function z_menu_todos($conn) {
$z_menu = "SELECT * FROM z_menu ORDER BY posicao ASC";
return $conn->prepare($z_menu);
}
However, it might be a good idea to create a separate class for managing your database connection and other stuff purely related to database and another class for executing SQL queries against your menu table.