[SOLVED] $this is confusing me - please help

[vr4lyfe]

dbLink is my db abstraction class.

This syntax work when I am using the class:

$connection = new dbLink("session");
$connection->query("sql goes here");

Now I am making another class, which uses and include_once() to integrate the db class and this syntax does not work:

$this->connection = new dbLink("session");
$this->connection->query("sql stuff goes here");

Can anyone help me with the proper syntax to make the second code fragment work?

Thanks!

[Balmung-San]

Does your class have a variable called $connection?

 

$this->connection does not use the $connection variable. In fact, it's quite gibberish to PHP.

 

$this->$connection is what you want.

[Jessica]

$this->connection is the proper way to access a class variable $connection, it isn't gibberish.

$this->$connection will look for a variable with the name that is the value of $connection.

 

IE:

$bar = 'foo';

$foo = 10;

 

echo $$bar; will print 10.

 

vr, I'm not sure you can just include the db class as a way to integrate it. If you post the two files we can try to help better.

[Balmung-San]

$this->connection is the proper way to access a class variable $connection, it isn't gibberish.

$this->$connection will look for a variable with the name that is the value of $connection.

 

Ugh, the pain of various OO systems.

 

Sorry, I originally learned OO with Java, and it took over my brain during my post. My natural assumption is that you'd use the variable's name (that is, with the $) as opposed to everything except the $.

[vr4lyfe]

class dbLink {

	var $server;				# server address
	var $username;				# username to connect with
	var $password;				# password to connect with
	var $database;				# name of database to use
	var $connection;			# database connection object
	var $errors;				# array to contain all errors encountered

	# CONSTRUCTOR

	function __construct($table_to_use) {

		# If new connection does not specify which database to connect to, default to localhost.

		switch($table_to_use){ 
			default: 
				$mysql_server_ip = 'localhost'; 
				break;
		}

		$mysql_db_name = 'facetime';

		if($_COOKIE['power'] == 0){
			# REGISTERED USER [2] || PAID USER [4] || RECRUITER [6]
			# connect to database as normal account
			$mysql_user 	= 'ft_user';
			$mysql_password = 'password';
		} else { 
			# GUESTS || 
			# connect to database as guest account with only SELECT priviledges
			$mysql_user 	= 'ft_guest';
			$mysql_password = 'password';
		}

		$this->connect($mysql_server_ip, $mysql_user, $mysql_password, $mysql_db_name);
	}

	# Creates connection to database

	function connect($server,$username,$password,$database){
		$this->server = $server;
		$this->username = $username;
		$this->password = $password;
		$this->database = $database;

		$this->connection = mysql_connect($this->server, $this->username, $this->password);

		if (!$this->connection) { $this->errors[] = mysql_error(); } 
			else {		
				if(!mysql_select_db($database, $this->connection)){	$this->errors[] = mysql_error(); }
			}
	}

	# Break connection to database

	function disconnect() {		}		

	# QUERIES

	# This function is the base wrapper to pass any sql statement (insert / delete / select)
	# Returns result object on success, or false on failure.

	function query($sql) {	if($result = mysql_query($sql, $this->connection)){		return $result;		} else { 	return false;	}	}

	# This function utilize the base db wrapper to execute select queries			
	# Return array of results on success to avoid user having to implement mysql_fetch calls.   Return false on failure.

	function select($sql) {
		if($result = $this->query($sql)){
			while($row = mysql_fetch_assoc($result)){	$result_array[] = $row;		}		
			return $result_array;
		} else {
			$this->errors[] = mysql_error();
			return false;
		}			
	}

}

[vr4lyfe]

class Session {

	var $sessionID;				# 
	var $userID;				#
	var $userhash;				# 
	var $userpower;				# 
	var $time;					# 
	var $connection;			# stores a connection to the db once made with the connect function
	var $errors;				# array to contain all errors encountered

	# CONSTRUCTOR

	function __construct() {

		# if session cookie is available pull from session db

		# if session cookie is not available, log error return false
		if(isset($_COOKIE['session'])){
			$this->connect();
			$tmp = $this->$connection->select("SELECT * FROM session");
			print_r($tmp);				
		} else {
			$this->errors[] = "No sessions found";
		}

	}

	# Creates connection to database that contains the session table

	function connect(){
		if(!include_once('./includes/class_dbLink.php')){ $this->errors[] = "Failed to include required file for database connection."; }
			else {	$this->$connection = new dbLink("session"); }			
	}

	# Break connection to database

	function disconnect() {		}		


}

[vr4lyfe]

Those are the two classes in question.  I am still nub to OO as this is my first attempt at OO PHP.  =]

 

The code in questions is in the constructor of the Session class. 

 

Thanks for the help guys

 

PS, I am using PHP Version 5.1.6

[Balmung-San]

Shouldn't you include_once the file outside that function? I'm not too sure, but I believe it wouldn't generate an error, but scope all of that class info to just within that function.

 

Try using the include_once within the class, but outside a function.

 

And wow, second person I've seen today using # for their comments.

[Jessica]

Try this:

move your include to the top, before the class declaration.

include_once('./includes/class_dbLink.php');

 

Then change the $this->$connections to $this->connection.

 

That should fix the problem.

 

Also, I don't believe include_once() will return a false value if the include fails - you might want to use require() instead of your if statement.

[vr4lyfe]

omg .. i m so sorry i wasted everyone's time .. i feel incredibly stupid right now.

 

I assumed the statement was not working since it was supposed to output some db result.  Turns out I forgot that my db was empty.

 

But yes, this is the correct syntax.

 

$this->varname->functionname();

 

Thanks to everyone who replied.  Have a great Friday all !!