# write dataframe to postgres
drv <- dbDriver("PostgreSQL")
con <- dbConnect(drv, host="localhost", user="postgres", password="zzzz", dbname="mydatabase", port="5436")
if(dbExistsTable(con,"myschema.tablex")) {
  dbRemoveTable(con,"myschema.vkt_tablex")}
dbWriteTable(con,"myschema.tablex", dataframe, row.names=F)

SET search_path = myschema, public;

library(RPostgreSQL);
drv <- dbDriver("PostgreSQL")
con <- dbConnect(drv, dbname="db", host="host", port=5432, user="user", password="pwd")
dbWriteTable(con, c("yourschema", "yourtable"), value = yourRdataframe)
dbDisconnect(con)