Good day, I read some data from a PostgreSQL database by a following script:
library(Rdbi) library(RdbiPgSQL) # conn becomes an object which contains the DB connection: conn <- dbConnect(PgSQL(), host="localhost", dbname="BVS", user="postgres", password = "*******") query_duj_kal <- dbSendQuery(conn, "select zdroj as well, cas as date, fe2, fe3, mn, nh4, no2, no3, o2, teplota as temperature from analystats where zdroj like 'Dunaj Kalinkovo'") watchem_duj_kal <- dbGetResult(query_duj_kal) My intention with the data is to create a time series by a following script: date <- (watchem_duj_kal$date) NO3 <- (watchem_duj_kal$no3) NH4 <- (watchem_duj_kal$nh4) maxy<-max(NO3,NH4) miny<-min(NO3[NO3>0],NH4[NH4>0]) date_p <- as.POSIXct(date, "CET") par(mfrow=c(2,1), ylog = TRUE, yaxp = c(0.01, 100, 3)) plot(date_p, NO3,log = "y", type = "l", col = "darkred", main = "NVZ-1", xlab = "time", ylab = "NO3-" ) lines(date_p, NH4, col = "darkblue", lty = "dotted") plot(date_p, NH4, log = "y", type = "l", col = "darkblue", main = "NVZ-1", xlab = "time", ylab = "NH4+" ) The first problems comes with the definition maxy and miny (following a previous advice od Christian Poersching through this mailing list) what worked pretty well with data imported from a csv file by a read.table() function, but in this case I got NA output The next problem comes with the unambiguous format od the "date" field, which is in the database defined as YYYY-MM-DD, but in the resulting "watchem_duj_kal" dataset is strangely converted to DD-MM-YYYY, what is unambiguous for the as.POSIXct() function expecting YYYY-MM-DD. A function converting the format of the date should help, but I could not find untill now. I appreciate every advice/suggestion/help. Best regards Tomas ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
