Using dbfaker
In dbfaker: A Tool to Ensure the Validity of Database Writes

Job Structure

# parse cli arguments 
library(optparse)
option_list <- list(
  make_option(c("-d", "--date"), 
              type="character", 
              default=as.character(as_date(with_tz(Sys.time(), "GMT"))),
              help="date of execution"),
  make_option(c("-t", "--test"),
              action="store_true",
              default=FALSE,
              help="execute tests and mask writes to databases")
)
opt <- parse_args(OptionParser(option_list=option_list))

# execute with parsed arguments
run(opt$date, opt$test)

# main function which encapsulates high level functions of your program
run <- function(date, test) {
  readData(...)
  transformData(...)
  trainModel(...)
  ifelse(test, dbfaker::verifyWrite(...), writeData(...))
}

# components of your program
readData <- function(...) {}
transformData <- function(...) {}
trainModel <- function(...) {}
writeData <- function(...) {
  dbWriteTable(...)
  dbSendQuery(...)
}