Dear All, I know rather little about the sql family of databases, but from time to time I have to access some data which is stored e.g. in a mysql database. I came across these posts http://bit.ly/WGyGTW http://bit.ly/VR4ZkN http://bit.ly/VR51t0 I am now surprised about the amount of data one can handle in R on a standard pc with some Gb of RAM. Please see the code at the end of the email. I read and entire database into x. x feels like a dataframe, but the is.data.frame(x) tells me that it is not. Knowing little about sql, can I in any case forget all the technicalities and treat x as if it was a data frame to carry out my analysis in R? Or is a word of caution in order? Many thanks Lorenzo ################################################################################ library(RMySQL) require(ETLUtils) login <- list() login$user <- "genome" login$host <- "genome-mysql.cse.ucsc.edu" x <- read.dbi.ffdf( query = "select * from mm9.knownGene", dbConnect.args = list(drv = dbDriver("MySQL"), user = login$user, host = login$host), VERBOSE=TRUE)