Passing db connection between functions

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();
 }
}

• Lawrence Cherone: your not returning the connection handler. $con from openconn()
• Decent Dabbler: Allen, I advise you to read up on the basics of Object Oriented Programming (OOP) and properties

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();