/**
	 * Execute an sql query, Cache the result if needed, Load the result
	 * if available.
	 *
	 * @global	object	$cache		Cache object included for sql caching
	 * @param	string	$sql		The sql query to be executed
	 * @param	boolean	$transact	Transact the query?
	 * @param	string	$cache_name	The cache handle for this query
	 * @return	mixed
	 */
	function sql_query($sql, $transact = false, $cache_name = false)
	{
		global $cache;
		
		// Increment the query counter.
		$this->stats['queries']++;
		
		// Check for caching
		if ( $cache_name != false )
		{
			// Allow the query to be cached without a handle
			if ( gettype($cache_name) == 'boolean' )
			{
				// The handle becomes an md5 string of the sql
				$cache_name = md5($sql);
			}
			
			// If not, execute and handle bad results.
			if ( ! $result = $this->layer->sql_query($sql, $transact) )
			{
				// Report a query error.
				trigger_error('Error_DB_Query', ERROR_DB);
			}
			
			// Attempt to load cache
			if ( ! $this->cache[$cache_name] = $cache->sql->load($cache_name) )
			{
				// If load fails, free var
				$this->sql_freeresult($result);
			}
			
			// Only execute if not already set
			if ( ! isset ( $this->cache[$cache_name] ) )
			{
				// Handle caching if needed
				$cache[$cache_name] = $this->sql_fetchrowset($result);
				$cache->sql->store($cache_name, $cache[$cache_name]);
				
				// Free the result
				$this->sql_freeresult($result);
			}
			
			// Return as cache handle
			$result = $cache_name;
			
			// Increment cached queries
			$this->stats['queries']++;
		}
		
		// Check if cache loaded
		if ( ! $result )
		{
			// If not, execute and handle bad results.
			if ( ! $result = $this->layer->sql_query($sql, $transact) )
			{
				// Report a query error.
				trigger_error('Error_DB_Query', ERROR_DB);
			}
		}
		
		// Return Identifier
		return $result;
	}