Passing db connection between functions - php

Question

I'm fairly new at PHP and so maybe this is a simple question. This is a class I use to update a database. The problem is that it keeps giving me an error at the line marked * because it can't find $con, which is clearly in the function openconn(). It seems I can't pass the connection to another function. Am I doing something wrong?Thanks
class retreats {
public $retreat_name = '';
function openconn() {
$con = mysql_connect("localhost","root","root");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("PHPTest", $con);
}
function closeconn(){
mysql_close($con);
}
function add_retreat(){
openconn();
$sql="INSERT INTO tbl_retreats (retreat_name) VALUES ('".$this->retreat_name."')";
if (!mysql_query($sql,$con)) *******
{
die('Error: ' . mysql_error());
}
echo "Record Successfully Added";
closeconn();
}
}

Answer 1

$con is a local variable for the function openconn. Try to change your code in this way:
class retreats {
public $retreat_name = '';
private $con;
function openconn() {
$this->con = mysql_connect("localhost","root","root");
if (!$this->con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("PHPTest", $this->con);
}
function closeconn(){
mysql_close($this->con);
}
function add_retreat(){
openconn();
$sql="INSERT INTO tbl_retreats (retreat_name) VALUES ('".$this->retreat_name."')";
if (!mysql_query($sql,$this->con))
{
die('Error: ' . mysql_error());
}
echo "Record Successfully Added";
closeconn();
}
}

Answer 2

A Simple PDO port of your code...
<?php
class pdoDB{
//PDO Connect
function connect($host,$db,$user,$pass){
$this->dbh = new PDO('mysql:host='.$host.';dbname='.$db, $user, $pass);
}
function query($query){
$this->retreat_name = $query;
$this->prepare();
}
function prepare(){
/* Execute a prepared statement by binding PHP variables */
$this->sth = $this->dbh->prepare('INSERT INTO tbl_retreats (retreat_name) VALUES (:value)');
$this->sth->bindParam(':value', $this->retreat_name);
$this->execute();
}
function execute(){
$this->sth->execute();
}
function result(){
if ($this->sth->rowCount() > 0) {
return 'Record Successfully Added';
}else{
return 'Record Not Inserted';
}
}
function close(){
$this->sth = null;
}
}
$db = new pdoDB();
$db->connect('localhost','PHPTest','root','pass');
$db->query('Barcelona'); //or $db->query($_POST['retreat_name']);
echo $db->result();
$db->close();
?>

Answer 3

You need to first declare the $con in the class. Just put it after the public $retreat_name = '';
put
public $retreat_name = '';
private $con;
after that, you can use it in other functions using the $this keyword.
mysql_close($this->con);

Answer 4

it turns out you need to do this
$this->openconn();
instead of just
openconn();