[R] Data frames in files - and - SQL with data frames

[Eduardo Henrique Altieri]

Since the databases that I handle with are very large, I need answers to some questions: 

1) Can I work with R data frames like databases in SAS, that is, storing data frames in files instead of in memory?

2) Can I use SQL codes to work with R data frames? Note that I ask for the direct use, with no need to use a “channel” or to export data frames to a DBMS.

Thanks.