<?php
/*
** Class: pvl_DAO
** Description: This is a lightweight DAO class. As opposed to some gigantic framework
**              that actually generates classes after reading tables in your db, this
**              works by being fed the table name at instantiation. Optionally, you
**              can provide the primary key as well, but if you don't, it will find out
**              on it's own.
**              Once again, this is very lightweight and isn't meant to be used in
**              complex scenarios.
** Author: TRC
*/
class pvl_DAO
	{
	/* public */ var $id=null;
	/* public */ var $data=null;
	/* public */ var $table=null;
	/* public */ var $primary=null;

    /* public */ var $type='';
    /* public */ var $error=null;                            // This is set by the factory

    /* public */ var $query=null;
    /* publice */ var $factory;


    # Constructor.
	function pvl_DAO()
		{ 
        // my_print_r($GLOBALS);
        // my_print_r($this);
        // $this->query=$GLOBALS[$this->factory]->returnObject('pvl_query');
        }
    # End function pvl_DAO()


    # Finish setting up the object and grab the info from the database
    function load($id, $table, $primary='')
        {
        // my_print_r($GLOBALS[$this->factory]);
        // my_print_r($this);
        $this->query=&$GLOBALS[$this->factory]->returnObject('pvl_query');
        $this->query->setupObject();
        my_print_r($this);


		# Let's first setup some vars
		$this->table=$table;
		$this->id=$id;
		if($primary=='')
			{ $this->primary=$this->findPrimary($this->table); }
		else
			{ $this->primary=$primary; }

		$SQL='SELECT * FROM '.$this->table.' WHERE '.$this->primary.' = '.$this->id;
		$this->query->dbQuery($SQL);
		while($row=$this->query->dbFetchArray('object'))
			{ $this->data=$row; }
        }
    # End function load()
    

    # Change or set a value in the object
	function set($key, $val)
		{
		if($this->checkKeyExistence($key)==true)
			{
			$this->data->$key=$val;
			return true;
			}
		else
			{ return false; }
		}
    # End function set()


    # Get a value from the object
	function get($key)
		{
		if($this->checkKeyExistence($key)==true)
			{ return $this->data->$key; }
		else
			{ return false; }
		}

	function checkKeyExistence($key)
		{
		if(array_key_exists($key, $this->data))
			{ return true; }
		else
			{ return false; }
		}
    # End function get()


    # Get the primary key for the table if one is not provided
	function findPrimary()
		{
		$SQL='SHOW COLUMNS FROM '.$this->table;
		$this->query->dbQuery($SQL);
		while ($row=$this->query->dbFetchArray('object'))
			{
			if($row->Key=='PRI')
				{ return $row->Field; }
			}
		}
    # End function findPrimary()


    # Write the data back to the datasource
	function writeData()
		{

		$SQL='UPDATE '.$this->table.' SET ';

		foreach($this->data as $k => $v)
			{
			if($k==$this->primary)
				{ continue; }
			$SQL.="$k = '$v', ";
			}

		$SQL.='WHERE '.$this->primary.' = '.$this->id;
		$SQL=str_replace(', WHERE', ' WHERE', $SQL);
		echo $SQL."\n";

		$this->query->dbQuery($SQL);
		echo mysql_error()."\n";
		}
    # End funciton writeData()

	}
# End class pvl_DAO

?>