niknakk / rsqlite

R interface for SQLite

RSQLite

RSQLite embeds the SQLite database engine in R, providing a DBI-compliant interface. SQLite is a public-domain, single-user, very light-weight database engine that implements a decent subset of the SQL 92 standard, including the core table creation, updating, insertion, and selection operations, plus transaction management.

You can install the latest released version from CRAN with:

install.packages("RSQLite")

Or install the latest development version from github with:

# install.packages("devtools")
devtools::install_github("RcppCore/Rcpp")
devtools::install_github("rstats-db/DBI")
devtools::install_github("rstats-db/RSQLite")

To install from github, you'll need a development environment.

Basic usage

library(DBI)
# Create an ephemeral in-memory RSQLite database
con <- dbConnect(RSQLite::SQLite(), ":memory:")

dbListTables(con)
dbWriteTable(con, "mtcars", mtcars)
dbListTables(con)

dbListFields(con, "mtcars")
dbReadTable(con, "mtcars")

# You can fetch all results:
res <- dbSendQuery(con, "SELECT * FROM mtcars WHERE cyl = 4")
dbFetch(res)
dbClearResult(res)

# Or a chunk at a time
res <- dbSendQuery(con, "SELECT * FROM mtcars WHERE cyl = 4")
while(!dbHasCompleted(res)){
  chunk <- dbFetch(res, n = 5)
  print(nrow(chunk))
}
# Clear the result
dbClearResult(res)

# Disconnect from the database
dbDisconnect(con)

Acknowledgements

Many thanks to Doug Bates, Seth Falcon, Detlef Groth, Ronggui Huang, Kurt Hornik, Uwe Ligges, Charles Loboz, Duncan Murdoch, and Brian D. Ripley for comments, suggestions, bug reports, and/or patches.

Update version of SQLite

1. Download latest SQLite source

   latest <- "http://www.sqlite.org/2015/sqlite-amalgamation-3080802.zip"
   tmp <- tempfile()
   download.file(latest, tmp)
   unzip(tmp, exdir = "src/", junkpaths = TRUE)
   unlink("src/shell.c")

2. Update DESCRIPTION for included version of SQLite

3. Update NEWS

Update datasets database

RSQLite includes one SQLite database (accessible from datasetsDb() that contains all data frames in the datasets package. This is the code that created it.

tables <- unique(data(package = "datasets")$results[, 3])
tables <- tables[!grepl("(", tables, fixed = TRUE)]

con <- dbConnect(SQLite(), "inst/db/datasets.sqlite")
for(table in tables) {
  df <- getExportedValue("datasets", table)
  if (!is.data.frame(df)) next
  
  message("Creating table: ", table)
  dbWriteTable(con, table, as.data.frame(df), overwrite = TRUE)
}