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#' Database versions of the nycflights13 data
#'
#' These functions cache the data from the `nycflights13` database in
#' a local database, for use in examples and vignettes. Indexes are created
#' to making joining tables on natural keys efficient.
#'
#' @keywords internal
#' @name nycflights13
NULL
# nocov start
#' @export
#' @rdname nycflights13
#' @param path location of SQLite database file
nycflights13_sqlite <- function(path = NULL) {
cache_computation("nycflights_sqlite", {
path <- db_location(path, "nycflights13.sqlite")
message("Caching nycflights db at ", path)
con <- DBI::dbConnect(RSQLite::SQLite(), dbname = path, create = TRUE)
copy_nycflights13(con)
})
}
#' @export
#' @rdname nycflights13
#' @param dbname,... Arguments passed on to [src_postgres()]
nycflights13_postgres <- function(dbname = "nycflights13", ...) {
cache_computation("nycflights_postgres", {
message("Caching nycflights db in postgresql db ", dbname)
con <- DBI::dbConnect(RPostgres::Postgres(), dbname = dbname, ...)
copy_nycflights13(con)
})
}
#' @rdname nycflights13
#' @export
has_nycflights13 <- function(type = c("sqlite", "postgres"), ...) {
if (!requireNamespace("nycflights13", quietly = TRUE)) return(FALSE)
type <- match.arg(type)
succeeds(switch(
type,
sqlite = nycflights13_sqlite(...),
postgres = nycflights13_postgres(...)
), quiet = TRUE)
}
#' @export
#' @rdname nycflights13
copy_nycflights13 <- function(con, ...) {
all <- utils::data(package = "nycflights13")$results[, 3]
unique_index <- list(
airlines = list("carrier"),
planes = list("tailnum")
)
index <- list(
airports = list("faa"),
flights = list(c("year", "month", "day"), "carrier", "tailnum", "origin", "dest"),
weather = list(c("year", "month", "day"), "origin")
)
tables <- setdiff(all, DBI::dbListTables(con))
# Create missing tables
for (table in tables) {
df <- getExportedValue("nycflights13", table)
message("Creating table: ", table)
copy_to(
con, df, table,
unique_indexes = unique_index[[table]],
indexes = index[[table]],
temporary = FALSE
)
}
invisible(con)
}
# nocov end
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