PHP PDO Database Connect Class

Question

This is what I have as my database class:

<?php
// Define configuration
define("DB_RDBMS", "mysql");
define("DB_HOST", "localhost");
define("DB_NAME", "ccaweb");
define("DB_USER", "ccawebroot");
define("DB_PASS", "Ni2o7AwE");

class database {

    // Database Managment System (Database Type)
    private $rdbms      = DB_RDBMS;

    // Database Host Address/IP
    private $dbhost     = DB_HOST;

    // Database Name
    private $dbname     = DB_NAME;

    // Database User Name
    private $dbuser     = DB_USER;

    // Database Password
    private $dbpass     = DB_PASS;

    //
    private $con = false;

    public function __construct ()
    {
        //connect to database
        if (!$this->con)
        {
            //not yet connected, make a connection
            try
            {
                $this->db = new PDO($this->rdbms.':host='.$this->dbhost.';dbname='.$this->dbname, $this->dbuser, $this->dbpass);
                $this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                $this->con = true;
                return $this->con;
            }
            catch (PDOException $e)
            {
                require_once('/error/database_error.php');
                $date = date("d/m : H:i : ");

                file_put_contents('logs/db.connection.error.txt', $date.$e->getMessage().PHP_EOL,FILE_APPEND);
                exit();
            }
        }
        else
        {
            //already connected - do nothing and show true
            return true;
        }
    }

}
?>

This is what I'm doing to use the class:

// Import database class file
include_once '../library/class/database.class.php';

//create new database instance
$db = new database();

// Create Table
$query = "DROP TABLE IF EXISTS `courseannouncement`;
CREATE TABLE IF NOT EXISTS `courseannouncement` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `courseId` varchar(10) NOT NULL,
  `title` varchar(100) NOT NULL,
  `announcementText` text NOT NULL,
  `createdBy` int(11) NOT NULL,
  `createdDate` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `deleted` int(1) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
)";

$sth = $db->prepare("$query");
$sth->execute();

?>

However Im getting the error that: Fatal error: Call to undefined method database::prepare() in D:..\installDatabase.php on line 22

So I tried changing the database class to

class database extends PDO {

but that still gives me an error

Can anyone point me in the direction of what I'm doing wrong? Is using a class best practice for PDO database connection?

Also, Should I be using singleton? I've seen various places where they've said it's good to, but also alot of posts where it's said it's bad to use singletons.

Probably want `$sth = $db->db->prepare("$query");` – Phylogenesis Aug 02 '13 at 15:49 — Phylogenesis, Aug 02 '13 at 15:49
Also, I would like to note, that PDO is **not** a database. – tereško Aug 02 '13 at 15:51 — tereško, Aug 02 '13 at 15:51

score 1 · Answer 1 · answered Aug 02 '13 at 15:53

Your logic is flawed. Your class doesn't extend PDO, it merely instantiates a PDO object internally, but never EXPOSES that object to anyone using your class.

If you had

$db->db->prepare(...)

then it'd work, because you'd be accessing the PDO object you created inside your object.

score 0 · Answer 2 · answered Aug 02 '13 at 15:53

Where do you define database::db? You need to have a method in your class that processes the query using your db member, since that is the PDO object.

class database {
private $db;
  ...
  public function exeQuery($query) {
    $sth = $this->db->prepare($query);
    ...
  }

  ..
}

If you expose member db as public, you can access the pdo object outside the class.. $db->db->prepare($query);

score -2 · Answer 3 · answered Aug 02 '13 at 15:49

-2

Im getting the error that: Fatal error: Call to undefined method database::prepare()

There are no prepare() method in your class. This is why you are getting this error.

So I tried changing the database class to class database extends PDO {

So try again.

answered Aug 02 '13 at 15:49

Your Common Sense

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PHP PDO Database Connect Class

3 Answers3