public function has($forClass, $forColumn = null)
	{
		$refTable = static::tableName();
		$forTable = $forClass::tableName();
		$refColumn = static::$idColumn;
		$forColumn = $forColumn ?: strtolower(static::modelName())."_id";

		$rows = Db::query("
			select F.*
			from $refTable as R, $forTable as F
			where R.$refColumn = F.$forColumn and R.$refColumn = :id
		", ["id" => $this->$refColumn], static::getDbName());

		if ($rows === false)
			return false;
		if (empty($rows))
			return null;
		
		// Populate model
		$forModel = new $forClass;
		foreach ($rows[0] as $col => $val) $forModel->$col = $forModel->decodeValue($val, $col);
		return $forModel;
	}
public function has($forClass, $forColumn = null)
	{
		$refTable = static::tableName();
		$forTable = $forClass::tableName();
		$refColumn = static::$idColumn;
		$forColumn = $forColumn ?: strtolower(static::modelName())."_id";

		$rows = Db::query("
			select F.*
			from $refTable as R, $forTable as F
			where R.$refColumn = F.$forColumn and R.$refColumn = :id
		", ["id" => $this->$refColumn], static::getDbName());

		if ($rows === false)
			return false;
		if (empty($rows))
			return null;
		
		// Populate model
		$forModel = new $forClass;
		foreach ($rows[0] as $col => $val) $forModel->$col = $forModel->decodeValue($val, $col);
		return $forModel;
	}
public function has ( $ forClass , $ forColumn = null ) { $ refTable = static :: tableName ( ) ; $ forTable = $ forClass :: tableName ( ) ; $ refColumn = static :: $ idColumn ; $ forColumn = $ forColumn ? : strtolower ( static :: modelName ( ) ) . "_id" ; $ rows = Db :: query ( "
			select F.*
			from $refTable as R, $forTable as F
			where R.$refColumn = F.$forColumn and R.$refColumn = :id
		" , [ "id" => $ this -> $ refColumn ] , static :: getDbName ( ) ) ; if ( $ rows === false ) return false ; if ( empty ( $ rows ) ) return null ; // Populate model
 $ forModel = new $ forClass ; foreach ( $ rows [ 0 ] as $ col => $ val ) $ forModel -> $ col = $ forModel -> decodeValue ( $ val , $ col ) ; return $ forModel ; }
One-to-one relationship

@param string	$forClass	foreign model class name
@param string	$forColumn	foreign column if it differs from className_id (ex. user_id)

@return Model|bool foreign model or false if fails
One - to - one relationship