how to connect to a postgreSQL database from R

PostgreSQL_Query.R

library(RPostgreSQL)                          #import the library
driver <- dbDriver('PostgreSQL')              #define the database driver
db <- dbConnect(driver, host='foobar_host',   #set the host to the postgreSQL IP or alias
                user='foo_bar',               #input username
                password='my_secret_code',    #input your password
                dbname='my_gp_db')            #input the name of the databse



myquery <- "SELECT 
	      col_one
	      ,col_two
	      ,col_three
	    FROM table_one a
	    INNER JOIN table_two b
	      ON a.id = b.a_id
	    WHERE
	      a.created_date > 2012
	    LIMIT 100;"

my.data <- dbGetQuery(db, myquery)            #assign results to a vector