How to replicate notification functionality for integration server46

I started working in 6X version but now has to work on 4.6 so got following questions
1.We need to use notification functionality for WmDB package for 4.6.
how it can be done? sholud we excute select service on that table using schdular for every5 seconds? or there is some other way like from Oracle databse trigger http call can be made to invoke webmethods service? your suggestions/experiences are highly appreciated.
2.How file polling is done in 4.6 version for IS