Numeric connection string parameters may be formatted incorrectly in connection string

[BSchamberger]

Hi odbc team,

odbc:::build_connection_string creates a connection string out of the parameters passed to DBI::dbConnect/odbc:::odbc_connect. In the case one of the parameters is a large numeric, it may be converted to scientific format, potentially yielding an incorrect or invalid connection string.

This has happened to me with the Simba Spark ODBC Driver DefaultStringColumnLength argument/connection attribute. My data contains a field that may store long JSON strings, hence I set DefaultStringColumnLength to a large number to err on the safe side

DBI::dbConnect(
  odbc::odbc(),
  Driver                    = "Simba Spark ODBC Driver",
  SparkServerType           = 3,
  Host                      = "[MY_HOST]",
  Port                      = 443,
  AuthMech                  = 3,
  UID                       = "token",
  PWD                       = "[MY_TOKEN]",
  ThriftTransport           = 2,
  HTTPPath                  = "[MY_PATH]",
  DefaultStringColumnLength = 100000
)

which leads to the following connection string generated by odbc:::build_connection_string

[1] "Driver=Simba Spark ODBC Driver;SparkServerType=3;...;DefaultStringColumnLength=1e+05"

The DefaultStringColumnLength=1e+05 part is silently ignored by the driver.

The workaround I currently use it to set the parameter to a string directly (DefaultStringColumnLength = "100000"). However, it may be nicer if these cases are handled in the package directly. This issue could be solved by changing the definition of odbc:::build_connection_string to explicitly avoid scientific notation with format(args, scientific = FALSE) instead of using args directly:

build_connection_string <- function(args = list(), string = NULL) {

  args_string <- paste(names(args), format(args, scientific = FALSE), sep = "=", collapse = ";")

  if (!is.null(string) && !grepl(";$", string) && length(args) > 0) {
    string <- paste0(string, ";")
  }

  paste0(string, args_string)
}

which yields

[1] "Driver=Simba Spark ODBC Driver;SparkServerType=3;...;DefaultStringColumnLength=100000"

My environment:

R version 4.5.0 (2025-04-11 ucrt)
Platform: x86_64-w64-mingw32/x64
Running under: Windows 11 x64 (build 26100)

Matrix products: default
  LAPACK version 3.12.1

locale:
[1] LC_COLLATE=English_United Kingdom.utf8 
[2] LC_CTYPE=English_United Kingdom.utf8   
[3] LC_MONETARY=English_United Kingdom.utf8
[4] LC_NUMERIC=C                           
[5] LC_TIME=English_United Kingdom.utf8    

time zone: Europe/Zurich
tzcode source: internal

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

loaded via a namespace (and not attached):
 [1] bit_4.6.0         odbc_1.6.1        glue_1.8.0        blob_1.2.4       
 [5] pkgconfig_2.0.3   bit64_4.6.0-1     lifecycle_1.0.4   cli_3.6.5        
 [9] vctrs_0.6.5       DBI_1.2.3         pkgload_1.4.0     compiler_4.5.0   
[13] rstudioapi_0.17.1 tools_4.5.0       hms_1.1.3         pillar_1.11.0    
[17] Rcpp_1.1.0        rlang_1.1.6