how to manipulate (best package) NoSQL data format in R

#1
Hi,

I'm trying to manage data in a NoSQL format. Example:

ID Date Rule
1 2016-02-03 A:20;B:30
2 2016-02-01 A:20
3 2016-01-01 B:50;C:10

I would like to be able to go through my data like Dataset[1["Rule]]
and also to create the frequency distribution of the kind of Rule in my dataset (how many A,B and so on).

My data are in a CSV file and I would like to import them and keep it in the best way as possible.

Is there any package that can help me with this?

Thanks,
A.