PDO Connection MySQL Functions - php

Question

The code that I will post works but I want to know if it's okay and safe. I will use it to connect my Android APP with my MySQL database.
Here I create the PDO connection. I don't know if I should create it in the construct or using a method. Right now I'm using the connect() method and get() to return the same object. Should I close the connection? Why?
db_config.php
private $db;
function __construct(){
}
function __destruct(){
}
public function connect(){
$host = "XXXXXXXX";
$dbname = "XXXXXXXX";
$username = "XXXXXXX";
$password = "XXXXXXXX";
$options = array(PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8');
try{
$this -> db = new PDO("mysql:host={$host};dbname={$dbname};charset=utf8", $username, $password, $options);
} catch (PDOException $ex) {
die("Failed to connect to the database: " . $ex->getMessage());
}
$this-> db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$this -> db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
return $this->db;
}
public function get(){
return $this -> db;
}
trainer_functions.php
In this code I have the functions that I will use to interact with the database. I initialize the connection in the construct and then I use the get() method to return the same connection everytime I need it. Is this okay?
private $db;
function __construct(){
require_once 'db_config.php';
$this->db = new DB_Connect();
$this->db->connect();
}
public function storeUser($json){
$obj = json_decode($json);
$email = $obj -> {"email"};
$pass = $obj -> {"password"
$query = "INSERT INTO USUARIOS (email, pass) VALUES (:email , :pass)";
$query_params = array(
':email' => $email,
':pass' => $pass
);
try {
$stmt = $this -> db -> **get()** -> prepare($query);
$result = $stmt -> execute($query_params);
//json response
}
catch (PDOException $ex) {
//json response
}
The last part of my test code are the calls to the functions using tags. I create a trainer_functions object, then I collect the parameters via POST and call the function with the object. Here I have two questions:
- I send a JSON. Should I send the tag inside or outside the JSON?
- I think here should close the connection because the request has already been completed. It is true?
I would make a good web service because it is the last project of my course and later it will be a personal project with some iOS integration.
Thank you very much.

Answer 1

I've no idea on other files you included (they are too hard to read) but to answer the question from the title: PDO is already a class. You don't need no more.
So, db_config.php
<?php
$host = "XXXXXXXX";
$dbname = "XXXXXXXX";
$username = "XXXXXXX";
$password = "XXXXXXXX";
$charset = 'utf8';
$options = array(
PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES $charset',
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
);
$dsn = "mysql:host=$host;dbname=$dbname;charset=$charset"
$db = new PDO($dsn, $username, $password, $options);
is all you need.