Add tested R query how-to and correct usage examples

README.md

@@ -34,6 +34,23 @@ ATTACH 'https://huggingface.co/datasets/Nason/fec-database/resolve/aee3ae8b28685
 SELECT CAND_ID,CAND_NAME FROM fec.candidates WHERE cycle=2026 AND CAND_OFFICE='H' ORDER BY CAND_ID LIMIT 5;
 ```
 
+### R with DBI and duckdb
+
+Install the dependencies once with `install.packages(c("DBI", "duckdb"))`.
+
+```r
+library(DBI)
+con <- dbConnect(duckdb::duckdb(config = list(memory_limit = "128MiB", threads = "1", max_temp_directory_size = "0B")))
+dbExecute(con, "INSTALL httpfs")
+dbExecute(con, "LOAD httpfs")
+dbExecute(con, "ATTACH 'https://huggingface.co/datasets/Nason/fec-database/resolve/aee3ae8b28685104765fb1b1e3ebc2588cb907a3/fec.duckdb' AS fec (READ_ONLY)")
+dbGetQuery(con, "SELECT CAND_ID, CAND_NAME FROM fec.candidates WHERE cycle = 2026 AND CAND_OFFICE = 'H' ORDER BY CAND_ID LIMIT 5")
+dbDisconnect(con, shutdown = TRUE)
+```
+
+DuckDB uses HTTP range requests; queries run on your machine and may need substantial memory or download data. A `LIMIT` does not guarantee a small scan.
+
+
 Install/upgrade Python with `python -m pip install --upgrade datapond` (the examples use 0.1.5), or install released R datapond from [CRAN](https://cran.r-project.org/package=datapond) with `install.packages("datapond")`. R 0.1.1 remains a separate development version. The catalog ID is `fec`.
 
 The file occupies 19.69 GiB on disk; that is not a RAM estimate. Remote execution can still transfer much of it. Contribution views aggregate large tables, so a final `LIMIT` does not guarantee a small scan. The SQL above sets limits before attachment; leave process and disk headroom, and expect larger queries to fail when spill is disabled.