Error

[unidox]

I have just started picking up PHP again, so my OOP skills are a bit rusty. I keep getting this error:

 

Fatal error: Using $this when not in object context in C:\wamp\www\core\dbClass.php on line 93

 

That line is:

 

$this->last_query = "Table: " . $table . "Query: " . $sql;

 

I am calling an sql function inside dbClass from userClass:

 

$query = dbClass::sql ( "users", "WHERE `id` = '$userId'" );

 

Any ideas what I am doing wrong? Thanks

[trq]

The sql method is static, you cannot use $this within a static method because you do not have an object to refer to.

[unidox]

Ok, so I can do two things to my understanding:

 

1)

Use $dbClass->sql instead of dbClass::sql

 

2)

Change $this->last_query to $last_query

 

Am I right?

[trq]

We would need to see more code. Generally though. Static methods get over used by people who don't know what they are doing / how they work.

 

A database class really needs to be instantiated because it should store at least a little state.

[unidox]

dbClass:

<?php



class dbClass {

private $last_error;

private $last_query;

private $row_count;



public $owner_email;



public $db_host;

public $db_username;

public $db_password;

public $db_table;

public $site_dir;



public $prefix;



private $link;



function __construct( $host, $username, $password, $table ) {

	$this->db_host = $host;

	$this->db_username = $username;

	$this->db_password = $password;

	$this->db_table = $table;

	$this->connect();

}

function connect () {

	$this->link = mysql_connect($this->db_host, $this->db_username, $this->db_password);



	if (!$this->link) {

		$this->last_error = mysql_error();

		return false;

	}

	if (!$this->select_table()) {

		return false;

	}

	return $this->link;

}

function select_table() {

	if (!mysql_select_db($this->db_table)) {

		$this->last_error = mysql_error();

		return false;

	}

	return true;

}

function sql($table, $sql) {

	$this->last_query = "Table: " . $table . "Query: " . $sql;

	$row = mysql_query("SELECT * FROM `" . $prefix . $table . "` " . $sql . "") or die ( mysql_error ( ) );

	if (!$row) {

		$this->last_error = mysql_error();

		return false;

	}

	$this->row_count = mysql_num_rows($row);

	return $row;

}

function get_row($result, $type="MYSQL_BOTH") {

	if (!$result) {

		$this->last_error = "Invalid resource identifier passed to get_row() function.";

		return false;

	}

	if ($type == 'MYSQL_ASSOC') $row = mysql_fetch_array($result, MYSQL_ASSOC);

	if ($type == 'MYSQL_NUM') $row = mysql_fetch_array($result, MYSQL_NUM);

	if ($type == 'MYSQL_BOTH') $row = mysql_fetch_array($result, MYSQL_BOTH); 

	if (!$row) return false;

	return $row;

}

function insert_sql($table, $sql1, $sql2) {

	$this->last_query = "Table: " . $table . "Query: " . $sql1 . " | " . $sql2;

	$row = mysql_query("INSERT INTO `" . $this->prefix . $table . "` (" . $sql1 . ") VALUES (" . $sql2 . ")") or die(mysql_error());

	if (!$row) {

		$this->last_error = mysql_error();

		return false;

	}

	return true;

}

function update_sql($table, $sql) {

	$this->last_query = "Table: " . $table . "Query: " . $sql;

	$row = mysql_query("UPDATE `" . $this->prefix . $table . "` " . $sql . "");

	if (!$row) {

		$this->last_error = mysql_error();

		return false;

	}

	return true;

}

function escape_sql($data) {

	return mysql_real_escape_string($data);

}

function print_last_error() {

	return $this->last_error;

}

function print_last_query() {

	return $this->last_query;

}

}



?>

 

Function being used inside userClass:

public function getData ( $userId, $rowName ) {

        $query = dbClass::sql ( "users", "WHERE `id` = '$userId'" );

        if ( mysql_num_rows( $query ) == 1 ) {

            $row = dbClass::get_row( $query );

        } else {

            return "Error: No rows in query.";

        }

        return $row[$rowName];

    }

 

 

[trq]

Pfff. You haven't even declared any methods within the dbClass as static.

 

This....

 

$query = dbClass::sql ( "users", "WHERE `id` = '$userId'" );

 

should be....

 

$db = new dbClass($host, $username, $password, $table);
$query = $db->sql("users", "WHERE `id` = '$userId'" );

 

ps: The $table variable is misleading, it should be $dbname or similar.

[unidox]

Well, the db is already declared inside index.php:

<?php
session_start( );

// exit ( $_SESSION['userId'] );

include ("../config.php");

include ("../core/coreClass.php");
include ("../core/dbClass.php");
include ("../core/userClass.php");

define (IN_SCRIPT, true);

$coreClass = new coreClass ( );
$dbClass = new dbClass ( $host, $username, $password, $table );
$userClass = new userClass ( );

if ( !$userClass->checkLoggedIn( ) ) {
    $currentPage = "login";
} elseif ( $coreClass->getGET("page") && file_exists ( "pages/".$coreClass->getGET("page").".php" ) ) {
    $currentPage = $coreClass->getGET("page");
} else {
    $currentPage = "home";
}
include ( "processors/".$currentPage.".php" );
include ( "pages/".$currentPage.".php" );
?>

 

[trq]

Still, it won't exists within the userClass.

[unidox]

Could I use a global?

[trq]

Could I use a global?

 

That would break any encapsulation you may have. Your design is pretty floored anyways though.

 

Ideally, you would pass your database object (ensuring it implements some interface) to the construct of the userClass.

[unidox]

What do you mean by floored?

[Pikachu2000]

I'd guess he means flawed.

[unidox]

Can I ask how I can improve it?

[trq]

Can I ask how I can improve it?

One thing would be to read my last reply.