stage_conn: create a cachable duckdb connection. In dev

Description

stage_conn is primarily intended for internal use by other overtureR functions. However, it can be called directly by the user whenever it is desirable to have direct access to the connection object. The core code is copied from duckdbfs, which deserves all credit for the implementation

Usage

stage_conn(
  dbdir = ":memory:",
  read_only = FALSE,
  bigint = "numeric",
  config = list(),
  ...
)
strike_stage(conn = stage_conn())

Value

a duckdb::duckdb()connection object

Arguments

dbdir: Location for database files. Should be a path to an existing directory in the file system. With the default (or ""), all data is kept in RAM.
read_only: Set to TRUE for read-only operation. For file-based databases, this is only applied when the database file is opened for the first time. Subsequent connections (via the same drv object or a drv object pointing to the same path) will silently ignore this flag.
bigint: How 64-bit integers should be returned. There are two options: "numeric" and "integer64". If "numeric" is selected, bigint integers will be treated as double/numeric. If "integer64" is selected, bigint integers will be set to bit64 encoding.
config: Named list with DuckDB configuration flags, see https://duckdb.org/docs/configuration/overview#configuration-reference for the possible options. These flags are only applied when the database object is instantiated. Subsequent connections will silently ignore these flags.
...: Further arguments passed to DBI::dbConnect
conn: A duckdb_connection object

Details

When first called (by a user or internal function), this function both creates a duckdb connection and places that connection into a cache (overturer_conn option). On subsequent calls, this function returns the cached connection, rather than recreating a fresh connection.

This frees the user from the responsibility of managing a connection object, because functions needing access to the connection can use this to create or access the existing connection. At the close of the global environment, this function's finalizer should gracefully shutdown the connection before removing the cache.

strike_stage closes the connection.

Examples

Run this code


con <- stage_conn()
strike_stage(con)

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