Feature: add warning for field.types fields specified don't match dataframe fields

[cnolanminich]

Issue Description and Expected Result

The values passed into field.types() may not match any values in the source dataframe. Desired result: the user receives a warning along the lines of Warning: columns {col_names} are listed in field.types argument but have no match in the dataframe.

I think this is the location that would require some modification: https://github.com/r-dbi/odbc/blob/master/R/Table.R#L140-L142

Database

Netezza 07.01.0000 Release 7.1.0.6-P2

Reproducible Example

This (slightly silly) example does not work, as TEXT_VAL is uppercase in the field.types but lowercase in the modified mtcars dataset.

library(DBI)
#> Warning: package 'DBI' was built under R version 3.5.1
library(odbc)
#> Warning: package 'odbc' was built under R version 3.5.1
con <- dbConnect(odbc::odbc(), dsn='QMR_DEV', believeNRows = FALSE)

data <- dplyr::mutate(mtcars, text_val = paste0(rep("x", 700), collapse = "" ) )
#> Warning: package 'bindrcpp' was built under R version 3.5.1

dbWriteTable(con, 
             "MTCARS", 
             data, 
             overwrite = TRUE, 
             field.types = list("TEXT_VAL" = "varchar(750)" ) )
#> Error in result_insert_dataframe(rs@ptr, values): nanodbc/nanodbc.cpp:1587: HY008: Operation canceled

Whereas this works:

``` r

library(DBI)
#> Warning: package 'DBI' was built under R version 3.5.1
library(odbc)
#> Warning: package 'odbc' was built under R version 3.5.1
con <- dbConnect(odbc::odbc(), dsn='QMR_DEV', believeNRows = FALSE)

data <- dplyr::mutate(mtcars, text_val = paste0(rep("x", 700), collapse = "" ) )
#> Warning: package 'bindrcpp' was built under R version 3.5.1

dbWriteTable(con, 
             "MTCARS", 
             data, 
             overwrite = TRUE, 
             field.types = list("text_val" = "varchar(750)" ) )

^{Created on 2019-04-09 by the reprex package (v0.2.1)}

Session Info

devtools::session_info()
#>
- Session info ------------------------------------------------------------------------------------------------------------------------
 setting  value                                      
 version  R version 3.5.0 Patched (2018-04-25 r74647)
 os       Windows 10 x64                             
 system   x86_64, mingw32                            
 ui       RStudio                                    
 language (EN)                                       
 collate  English_United States.1252                 
 ctype    English_United States.1252                 
 tz       America/New_York                           
 date     2019-04-09                                 

- Packages ----------------------------------------------------------------------------------------------------------------------------
 package     * version date       lib source        
 assertthat    0.2.0   2017-04-11 [1] CRAN (R 3.5.1)
 backports     1.1.3   2018-12-14 [1] CRAN (R 3.5.2)
 base64enc     0.1-3   2015-07-28 [1] CRAN (R 3.5.0)
 bindr         0.1.1   2018-03-13 [1] CRAN (R 3.5.1)
 bindrcpp    * 0.2.2   2018-03-29 [1] CRAN (R 3.5.1)
 bit           1.1-14  2018-05-29 [1] CRAN (R 3.5.0)
 bit64         0.9-7   2017-05-08 [1] CRAN (R 3.5.0)
 blob          1.1.1   2018-03-25 [1] CRAN (R 3.5.1)
 callr         3.0.0   2018-08-24 [1] CRAN (R 3.5.1)
 cli           1.0.1   2018-09-25 [1] CRAN (R 3.5.1)
 clipr         0.4.1   2018-06-23 [1] CRAN (R 3.5.1)
 crayon        1.3.4   2017-09-16 [1] CRAN (R 3.5.1)
 DBI         * 1.0.0   2018-05-02 [1] CRAN (R 3.5.1)
 desc          1.2.0   2018-05-01 [1] CRAN (R 3.5.1)
 devtools      2.0.1   2018-10-26 [1] CRAN (R 3.5.2)
 digest        0.6.18  2018-10-10 [1] CRAN (R 3.5.1)
 dplyr         0.7.8   2018-11-10 [1] CRAN (R 3.5.2)
 evaluate      0.12    2018-10-09 [1] CRAN (R 3.5.1)
 fs            1.2.6   2018-08-23 [1] CRAN (R 3.5.1)
 glue          1.3.0   2018-07-17 [1] CRAN (R 3.5.1)
 hms           0.4.2   2018-03-10 [1] CRAN (R 3.5.1)
 htmltools     0.3.6   2017-04-28 [1] CRAN (R 3.5.1)
 knitr         1.20    2018-02-20 [1] CRAN (R 3.5.1)
 magrittr      1.5     2014-11-22 [1] CRAN (R 3.5.1)
 memoise       1.1.0   2017-04-21 [1] CRAN (R 3.5.1)
 odbc        * 1.1.6   2018-06-09 [1] CRAN (R 3.5.1)
 pillar        1.3.1   2018-12-15 [1] CRAN (R 3.5.2)
 pkgbuild      1.0.2   2018-10-16 [1] CRAN (R 3.5.1)
 pkgconfig     2.0.2   2018-08-16 [1] CRAN (R 3.5.1)
 pkgload       1.0.2   2018-10-29 [1] CRAN (R 3.5.1)
 prettyunits   1.0.2   2015-07-13 [1] CRAN (R 3.5.1)
 processx      3.2.0   2018-08-16 [1] CRAN (R 3.5.1)
 ps            1.2.1   2018-11-06 [1] CRAN (R 3.5.1)
 purrr         0.2.5   2018-05-29 [1] CRAN (R 3.5.1)
 R6            2.3.0   2018-10-04 [1] CRAN (R 3.5.1)
 Rcpp          1.0.0   2018-11-07 [1] CRAN (R 3.5.1)
 remotes       2.0.2   2018-10-30 [1] CRAN (R 3.5.1)
 reprex        0.2.1   2018-09-16 [1] CRAN (R 3.5.1)
 rlang         0.3.0.1 2018-10-25 [1] CRAN (R 3.5.1)
 rmarkdown     1.11    2018-12-08 [1] CRAN (R 3.5.2)
 rprojroot     1.3-2   2018-01-03 [1] CRAN (R 3.5.1)
 rstudioapi    0.8     2018-10-02 [1] CRAN (R 3.5.1)
 sessioninfo   1.1.1   2018-11-05 [1] CRAN (R 3.5.1)
 testthat      2.0.1   2018-10-13 [1] CRAN (R 3.5.2)
 tibble        1.4.2   2018-01-22 [1] CRAN (R 3.5.1)
 tidyselect    0.2.5   2018-10-11 [1] CRAN (R 3.5.1)
 usethis       1.4.0   2018-08-14 [1] CRAN (R 3.5.1)
 whisker       0.3-2   2013-04-28 [1] CRAN (R 3.5.1)
 withr         2.1.2   2018-03-15 [1] CRAN (R 3.5.1)

[1] C:/Users/minichc/R/win-library/3.5
[2] C:/Program Files/R/R-3.5.0patched/library

I'd be happy to submit a PR with a prototype of this functionality if this is a desirable feature.

[jimhester]

Sure we would be happy for a PR if you are interested!