无法使用dplyr访问现有的MonetDB

Question

I created a MonetDBLite database yesterday, populated it, and was accessing it with dplyr , however this morning I don't seem able to use dplyr .

Here's my connection:

statcast_db <- MonetDBLite::src_monetdblite("/Users/williampetti/statcast_database/statcast_db_Monet", create = FALSE)

And here's a simple query for the statcast_17 table:

statcast_db %>% 
    tbl("statcast_17") %>% 
    select(game_date) %>% 
    distinct() %>% 
    collect() %>% 
    tail(n = 1)

Yesterday, this worked fine. This morning, I get this error:

Error in UseMethod("db_query_fields") : 
  no applicable method for 'db_query_fields' applied to an object of class "MonetDBEmbeddedConnection"

If I use a simple dbGetQuery call, however, it works fine:

> dbGetQuery(statcast_db$con, "SELECT game_date FROM statcast_17 ORDER BY game_date DESC LIMIT 1")
   game_date
1 2017-04-29

Here's my session info:

> sessionInfo()
R version 3.3.1 (2016-06-21)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: OS X 10.11.6 (El Capitan)

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

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

other attached packages:
 [1] xml2_1.1.1        baseballr_0.3.1   RSQLite_1.0.0     pacman_0.4.1     
 [5] dplyr_0.5.0       purrr_0.2.2       readr_1.0.0       tidyr_0.6.0      
 [9] tibble_1.2        ggplot2_2.2.1     tidyverse_1.0.0   magrittr_1.5     
[13] MonetDBLite_0.3.1 RMySQL_0.10.9     DBI_0.5-1        

loaded via a namespace (and not attached):
 [1] splines_3.3.1       lattice_0.20-33     colorspace_1.2-6   
 [4] htmltools_0.3.5     mgcv_1.8-12         chron_2.3-47       
 [7] XML_3.98-1.6        survival_2.40-1     hexbin_1.27.1      
[10] foreign_0.8-66      RColorBrewer_1.1-2  plyr_1.8.4         
[13] stringr_1.2.0       munsell_0.4.3       gtable_0.2.0       
[16] rvest_0.3.2         XML2R_0.0.6         codetools_0.2-14   
[19] latticeExtra_0.6-28 knitr_1.14          reldist_1.6-6      
[22] htmlTable_1.7       Rcpp_0.12.9         acepack_1.4.1      
[25] scales_0.4.1        pitchRx_1.8.2       Hmisc_4.0-0        
[28] gridExtra_2.2.1     digest_0.6.11       stringi_1.1.3      
[31] grid_3.3.1          tools_3.3.1         bitops_1.0-6       
[34] lazyeval_0.2.0      RCurl_1.95-4.8      Formula_1.2-1      
[37] cluster_2.0.4       MASS_7.3-45         Matrix_1.2-6       
[40] data.table_1.9.6    lubridate_1.6.0     httr_1.2.1         
[43] assertthat_0.1      R6_2.1.3            rpart_4.1-10       
[46] nnet_7.3-12         nlme_3.1-128   

Answer 1

I just replied to a similar question this morning after figuring out that the order in which you load MonetDBLite matters. I came across this question trying to figure out why it does matter. I was having the same type of Error in UseMethod problems as BillPetti. Making sure MonetDBLite loads after dplyr and dbplyr has resolved the issue for me. Here's the link to that other answer:

https://stackoverflow.com/a/53307673/3705612