#load in required libraries
library(RPostgreSQL)

#connect to database
drv <- dbDriver("PostgreSQL")
DB <- dbConnect(drv, dbname = "dbname", user = "user",
                      host = "host",
                      password = "password", port = "5432")
#pull in shapefile data
world.shp <- dbReadTable(DB, "ne_10m_admin_1_states_provinces")

require(rgdal)
dsn="PG:dbname='gis'"