update table in postgresql database through r

Question

How do I update data in a postgresql db through R with new data?

I've tried

dbGetQuery(con,"UPDATE table SET column1=:1,column2=:2, column3=:3 
              where id=:4", data=Rdata[,c("column1", "column3", "column3","id")])

I also tried with the colons replaced with $ but that didn't work either. I keep getting:

Error in postgresqlExecStatement(conn, statement, ...) : 
unused argument(s)

Answer 1

I figured it out using:

update <- function(i) {
drv <- dbDriver("PostgreSQL")
con <- dbConnect(drv, dbname="db_name", host="localhost", port="5432", user="chris", password="password")
txt <- paste("UPDATE data SET column_one=",data$column_one[i],",column_two=",data$column_two[i]," where id=",data$id[i])
dbGetQuery(con, txt)
dbDisconnect(con)
}


registerDoMC()

foreach(i = 1:length(data$column_one), .inorder=FALSE,.packages="RPostgreSQL")%dopar%{
update(i)
}

Answer 2

At least the RODBC has a specific function sqlUpdate:

sqlUpdate updates the table where the rows already exist. Data frame dat should contain columns with names that map to (some of) the columns in the table

See http://cran.r-project.org/web/packages/RODBC/RODBC.pdf