Connect to CalCOFI Database — cc_get

Connects to a frozen CalCOFI DuckLake release. Downloads and caches the database locally for fast subsequent access.

Usage

cc_get_db(
  version = "latest",
  local_cache = TRUE,
  cache_dir = NULL,
  refresh = FALSE,
  local_data = FALSE,
  tables = NULL
)

Arguments

version: Version string (e.g., "v2026.02") or "latest" (default)
local_cache: Use local cache if available (default: TRUE)
cache_dir: Directory for local cache. Default uses rappdirs::user_cache_dir("calcofi4r") if rappdirs is installed, otherwise a temp directory.
refresh: Force re-download even if cached (default: FALSE)
local_data: Download parquet files locally and create tables instead of remote views (default: FALSE). Useful for apps that need fast local queries without network overhead.
tables: Character vector of table names to include. NULL (default) includes all tables. Use to exclude large tables like CTD data.

Value

DuckDB connection object

Details

The frozen releases contain clean, stable data without provenance columns, suitable for analysis and visualization. Use cc_list_versions() to see available releases.

When local_data = FALSE (default), the connection points to Parquet files from the frozen release registered as views in DuckDB. This allows querying without downloading the entire database.

When local_data = TRUE, parquet files are downloaded to cache_dir/parquet/{version}/ and loaded as local tables for faster queries. Files are only downloaded if missing or if refresh = TRUE.

Data is stored at gs://calcofi-db/ducklake/releases/{version}/.

Examples

if (FALSE) { # \dontrun{
# connect to latest release (remote views)
con <- cc_get_db()
DBI::dbListTables(con)

# connect with local data (downloads parquets)
con <- cc_get_db(local_data = TRUE, cache_dir = "data")

# exclude CTD tables
con <- cc_get_db(
  local_data = TRUE,
  tables     = setdiff(cc_db_info()$tables$name,
    c("ctd_cast", "ctd_measurement", "ctd_summary")))
} # }