ROracle dbGetQuery bind parameters by name - r

Question

I am trying to process a large number of queries with parameters in R using ROracle. I know which parameters appear in each query, but I don't know in which order they appear. I am therefore looking for a way to submit the parameters by name in each query. Sample code:
library(ROracle)
# establish connection to DB
drv <- dbDriver("Oracle")
con <- dbConnect(drv, "User", "password", dbname = "DB")
# create table
createTab <- "create table RORACLE_TEST(num1 number, num2 number)"
dbGetQuery(con, createTab)
# insert String
insStr <- "insert into RORACLE_TEST values(:row1, :row2)"
dbGetQuery(con, insStr, data.frame(row2 = 0, row1 = 1))
# check output
dbGetQuery(con, "SELECT * FROM RORACLE_TEST")
# Output is:
# NUM1 NUM2
#1 0 1
# Desired output should be:
# NUM1 NUM2
#1 1 0
Any workaround for this will be appreciated except solutions of the kind
dbGetQuery(con,gsub(":row2", "0", gsub(":row1", "1", insStr)))
since this will not sanitize against sql injection (parameters will come from user input).

Answer 1

I have spent some time on the same question recently myself and found no perfect solution for this. In my opinion it is very wrong from syntax point of view to use named placeholders as it gives impression that argument order is insignificant.
I believe this is not the issue nor responsibility of ROracle library as this also would lead to a result which for person who doesn't know PL/SQL good enough is not expected:
DEFINE
row1 number;
row2 number;
BEGIN
row1 := 1;
row2 := 0;
EXECUTE IMMEDIATE 'insert into RORACLE_TEST values(:row1, :row2)' USING row2, row1;
END;
/
As we migrated our applications from RODBC with RODBCext to ROracle, we kept using ? as a bind variable placeholder and replaced them with colon style in our database connectivity API. At least this shouldn't raise anyone's eyebrows:
# placeholders '?' are replaced with :1 and :2 in custom_dbGetQuery()
insStr <- "insert into RORACLE_TEST values(?, ?)"
custom_dbGetQuery(con, insStr, data.frame(row2 = 0, row1 = 1))
Edit: added suggestion to reorder data frame
You could go further by reordering the data frame yourself by checking placeholder occurrences in the query string:
custom_dbGetQuery <- function(con, insStr, data) {
names <- names(data)
name.pos <- sort(sapply(names, function(ph) {
regexp <- paste0(":", ph, "[^\\w]")
matches <- gregexpr(regexp, insStr, perl = TRUE)
matches <- unlist(matches)
stopifnot(length(matches) == 1, all(matches != -1))
matches
}))
data <- data[, names(name.pos)]
print("running query:")
print(insStr)
print("using data:")
print(data)
dbGetQuery(con, insStr, data)
}
insStr <- "insert into RORACLE_TEST values(:row1, :row2)"
custom_dbGetQuery(con, insStr, data.frame(row2 = 0, row1 = 1))
# Output:
# [1] "running query:"
# [1] "insert into RORACLE_TEST values(:row1, :row2)"
# [1] "using data:"
# row1 row2
# 1 1 0

Answer 2

A tidyverse solution inspired by sqlInterpolate (thanks #Scarabee!):
readr::read_file('query.sql') %>%
stringr::str_replace_all(., ':','?') %>%
DBI::sqlInterpolate(con, ., row2 = 0, row1 = 1) %>%
DBI::dbGetQuery(con, .)