PHP/MySQL Help With OOP

[Kipkip]

<?php
class MySQL
{
  var $row;
  function add_cat($name)
	{
	  $insert = "INSERT INTO Catergories(Name) VALUES ($this->name)";
		if(mysql_query($this->insert)){
		  return true;
	  }else{
		  return false;
		}
	}
	function show_cat()
	{
	  $query = mysql_query("SELECT ID, Name FROM Catergories ORDER BY Name");
    while ($this->row = mysql_fetch_array($this->query) or die(mysql_error())){
      $id = $this->row['id'];
      $name = $this->row['name'];
      print("<a href=\"?delete=$this->id\">$this->name</a><br />");
    }
	}
	function delete_cat( $id )
	{
	  $query = "DELETE FROM Catergories WHERE ID = $this->id";
		if(mysql_query($this->query)){
		  return true;
		}else{
		  return false;
		}
	}
}
?>

In the add_cat() function, it won't submit the thing and returns false, getting one of my errors. And the show_cat() function shows this error:

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in /home/kipkip/public_html/news/admin/function_list_cat.php on line 17

Help. I'm just learning OOP.

 

[Imakuni?]

let me see if i understand what you are doing

      $insert = "INSERT INTO Catergories(Name) VALUES ($this->name)";
        if(mysql_query($this->insert)){
          return true ();
      }else{
          return false ();
        }

try working with that

 

[JDS]

Remember, anytime you use $this, it refers to variables or functions that are created within that class only. So, to start, at the beginning of your script, you'll also want to declare

var $insert;
var $query;

Now, for your function, anytime you're wanting to work with a variable from inside the class, you always have to prefix it with $this->. However, if you're inside of a function and you're using one of the arguments provided to the function (as in: add_cat($name), you would refer to the variable $name WITHOUT the $this-> prefix). So, rewriting the first function:

  function add_cat($name) 
  { 
      $this->insert = "INSERT INTO Catergories(Name) VALUES ($name)"; 
      if(mysql_query($this->insert))
      { 
          return true; 
      }
      else
      { 
          return false; 
      } 
  }

See if that helps out.
Cheers, John

 

[Kipkip]

No, that still doesn't help, JDS. I'm probally going to figure out this error using dumb luck like the last time. :D

 

[JDS]

Well, that's just to fix that one function - you have other things in your class missing, such as a valid MySQL connection.

Here, I'll post the class I made for PPN's pokedex and let you look over it.

/* Class File */

//////////////////////////////////////////////////////
//
//		Dataase Connection Class
//			Copyright 2004 John Slone
//
//
//////////////////////////////////////////////////////


/* Database class */
// Handles all interaction with database

class DB {
	
	var $username = 'root';
	var $password = '';
	var $database = 'JWAC';
	var $host = 'localhost';
	var $result = array();
	
	var $connect_id = 0;
	var $query_id = 0;
	
	var $querycount = 0;
	var $tempquerycount = 0;
	
	// Beginning of functions
	
	// Connect function
	// -connects to database
	
	function connect() {
		
		if (0 == $this->connect_id) {
			// No connection present.
			// Do we have a password?
			if (!$this->password) {
				$this->connect_id = mysql_connect($this->host,$this->username);
			} else {
				$this->connect_id = mysql_connect($this->host,$this->username,$this->password);
			}
			
		}
		
		if (!$this->connect_id) {
			exit("<b>Fatal Error:</b> Unable to connect to the database using those settings.");
		} else {
			if (!mysql_select_db($this->database,$this->connect_id)) {
				exit("<b>Fatal Error:</b> Unable to select $this->database for viewing.");
			}
		}
	}
	
	// Query function
	// performs an SQL query
	
	function query($queryline) {
		global $querycount;
		if (!$queryline) {
			exit("You must specify a query to execute.");
		} else {
			$this->query_id = @mysql_query($queryline, $this->connect_id);
// 			if (!$this->query_id) {
// 				die ("<i>$queryline</i> did not execute.<br />".mysql_error());
// 			}
			$this->querycount++;
		}
		if (!$this->query_id) {
			return false;
		}
		return $this->query_id;
	}
	
	function fetch($query_id) {
		if ($query_id) {
			$this->query_id = $query_id;
		}
		return @mysql_fetch_array($this->query_id);
	}
	
	// Num rows function
	// tells the number of rows in a result set.
	
	function numrows($query_id) {
		if ($query_id) {
			$this->query_id = $query_id;
		}
		return @mysql_num_rows($this->query_id);
	}
	
	// insert_id function
	// gets the autokey entry for the last inserted() row
	
	function insert_id() {
		return @mysql_insert_id($this->connect_id);
	}
	
}

See if that helps.

 

[Kipkip]

Ok. Here's the whole file now:

<?php
class MySQL
{
    //////////
    //Database Connection Variables
	//////////
	var $dbname = "news";
	var $dbuser = "root";
	var $dbpass = "<PASSWORD>";
	var $dbhost = "localhost";
	//////////
	//Other Variables
	//////////
	var $row;
	var $insert;
    var $query = "mysql_query(\"SELECT ID, name FROM Catergories ORDER BY Name\")";
	var $delete;
	var $id;
	var $name;
	//////////
	//Functions
	//////////
	function connection()
	  {
		  mysql_connect ($this->dbhost, $this->dbuser, $this->dbpass) or die ('I cannot connect to the database because: ' . mysql_error());
      mysql_select_db ($this->dbname);
		}
  function add_cat($name)
    {
      $this->insert = "INSERT INTO Catergories(Name) VALUES ($name)";
      if(mysql_query($this->insert)){
        return true;
      }else{
			  return false;
      }
    } 
	function show_cat()
	{
    while ($this->row = mysql_fetch_array($this->query) or die){
      $this->id = $this->row['ID'];
      $this->name = $this->row['name'];
      print("<a href=\"?delete=$this->id\">$this->name</a><br />");
    }
	}
	function delete_cat($id)
	{ 
	  $this->delete = mysql_query("DELETE FROM Catergories WHERE ID = $id");
		if($this->delete){
		  return true;
		}else{
		  return false;
		}
	}
}
?>

Still won't work. :\

 

[JDS]

And how are you calling the database class in your script?

 

[Kipkip]

And how are you calling the database class in your script?

Like this:

$new = new MySQL;
$new->connection();

EDIT: Apparently, there was something wrong with the database I was using. I swithed to another database and evrything is now working fine. I'm going to look into what went wrong with the database. Thanks for you help, JDS.