Package 'duckdb'

Title: DBI Package for the DuckDB Database Management System
Description: The DuckDB project is an embedded analytical data management system with support for the Structured Query Language (SQL). This package includes all of DuckDB and a R Database Interface (DBI) connector.
Authors: Hannes Mühleisen [aut] , Mark Raasveldt [aut] , Kirill Müller [cre] , Stichting DuckDB Foundation [cph], Apache Software Foundation [cph], PostgreSQL Global Development Group [cph], The Regents of the University of California [cph], Cameron Desrochers [cph], Victor Zverovich [cph], RAD Game Tools [cph], Valve Software [cph], Rich Geldreich [cph], Tenacious Software LLC [cph], The RE2 Authors [cph], Google Inc. [cph], Facebook Inc. [cph], Steven G. Johnson [cph], Jiahao Chen [cph], Tony Kelman [cph], Jonas Fonseca [cph], Lukas Fittl [cph], Salvatore Sanfilippo [cph], Art.sy, Inc. [cph], Oran Agra [cph], Redis Labs, Inc. [cph], Melissa O'Neill [cph], PCG Project contributors [cph]
Maintainer: Kirill Müller <[email protected]>
License: MIT + file LICENSE
Version: 1.0.0
Built: 2024-06-22 09:43:31 UTC
Source: https://github.com/duckdb/duckdb-r

Help Index


DuckDB SQL backend for dbplyr

Description

This is a SQL backend for dbplyr tailored to take into account DuckDB's possibilities. This mainly follows the backend for PostgreSQL, but contains more mapped functions.

tbl_file() is an experimental variant of dplyr::tbl() to directly access files on disk. It is safer than dplyr::tbl() because there is no risk of misinterpreting the request, and paths with special characters are supported.

tbl_query() is an experimental variant of dplyr::tbl() to create a lazy table from a table-generating function, useful for reading nonstandard CSV files or other data sources. It is safer than dplyr::tbl() because there is no risk of misinterpreting the query. Use dplyr::tbl(src, dplyr::sql("SELECT ... FROM ...")) for custom SQL queries. See https://duckdb.org/docs/data/overview for details on data importing functions.

Usage

simulate_duckdb(...)

translate_duckdb(...)

tbl_file(src, path, ..., cache = FALSE)

tbl_query(src, query, ..., cache = FALSE)

Arguments

...

Any parameters to be forwarded

src

A duckdb connection object

path

Path to existing Parquet, CSV or JSON file

cache

Enable object cache for Parquet files

query

SQL code, omitting the FROM clause

Examples

library(dplyr, warn.conflicts = FALSE)
con <- DBI::dbConnect(duckdb(), path = ":memory:")

dbiris <- copy_to(con, iris, overwrite = TRUE)

dbiris %>%
  select(Petal.Length, Petal.Width) %>%
  filter(Petal.Length > 1.5) %>%
  head(5)

DBI::dbDisconnect(con, shutdown = TRUE)

Connect to a DuckDB database instance

Description

duckdb() creates or reuses a database instance.

duckdb_shutdown() shuts down a database instance.

Return an adbcdrivermanager::adbc_driver() for use with Arrow Database Connectivity via the adbcdrivermanager package.

dbConnect() connects to a database instance.

dbDisconnect() closes a DuckDB database connection. The associated DuckDB database instance is shut down automatically, it is no longer necessary to set shutdown = TRUE or to call duckdb_shutdown().

Usage

duckdb(
  dbdir = DBDIR_MEMORY,
  read_only = FALSE,
  bigint = "numeric",
  config = list()
)

duckdb_shutdown(drv)

duckdb_adbc()

## S4 method for signature 'duckdb_driver'
dbConnect(
  drv,
  dbdir = DBDIR_MEMORY,
  ...,
  debug = getOption("duckdb.debug", FALSE),
  read_only = FALSE,
  timezone_out = "UTC",
  tz_out_convert = c("with", "force"),
  config = list(),
  bigint = "numeric"
)

## S4 method for signature 'duckdb_connection'
dbDisconnect(conn, ..., shutdown = TRUE)

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.

drv

Object returned by duckdb()

...

Ignored

debug

Print additional debug information such as queries

timezone_out

The time zone returned to R, defaults to "UTC", which is currently the only timezone supported by duckdb. If you want to display datetime values in the local timezone, set to Sys.timezone() or "".

tz_out_convert

How to convert timestamp columns to the timezone specified in timezone_out. There are two options: "with", and "force". If "with" is chosen, the timestamp will be returned as it would appear in the specified time zone. If "force" is chosen, the timestamp will have the same clock time as the timestamp in the database, but with the new time zone.

conn

A duckdb_connection object

shutdown

Unused. The database instance is shut down automatically.

Value

duckdb() returns an object of class duckdb_driver.

dbDisconnect() and duckdb_shutdown() are called for their side effect.

An object of class "adbc_driver"

dbConnect() returns an object of class duckdb_connection.

Examples

library(adbcdrivermanager)
with_adbc(db <- adbc_database_init(duckdb_adbc()), {
  as.data.frame(read_adbc(db, "SELECT 1 as one;"))
})

drv <- duckdb()
con <- dbConnect(drv)

dbGetQuery(con, "SELECT 'Hello, world!'")

dbDisconnect(con)
duckdb_shutdown(drv)

# Shorter:
con <- dbConnect(duckdb())
dbGetQuery(con, "SELECT 'Hello, world!'")
dbDisconnect(con, shutdown = TRUE)

DuckDB EXPLAIN query tree

Description

DuckDB EXPLAIN query tree


Get the Substrait plan for a SQL query Transforms a SQL query into a raw vector containing the serialized Substrait query blob

Description

Get the Substrait plan for a SQL query Transforms a SQL query into a raw vector containing the serialized Substrait query blob

Usage

duckdb_get_substrait(conn, query, enable_optimizer = TRUE)

Arguments

conn

A DuckDB connection, created by dbConnect().

query

The query string in SQL

enable_optimizer

Optional parameter to enable/disable query-optimizer. By default optimizer is enabled.

Value

A raw vector containing the substrait protobuf blob


Get the Substrait plan for a SQL query in the JSON format Transforms a SQL query into a vector containing the serialized Substrait query JSON

Description

Get the Substrait plan for a SQL query in the JSON format Transforms a SQL query into a vector containing the serialized Substrait query JSON

Usage

duckdb_get_substrait_json(conn, query, enable_optimizer = TRUE)

Arguments

conn

A DuckDB connection, created by dbConnect().

query

The query string in SQL

enable_optimizer

Optional parameter to enable/disable query-optimizer. By default optimizer is enabled.

Value

A vector containing the substrait protobuf JSON


Query DuckDB using Substrait Method for interpreting a Substrait BLOB plan as a DuckDB Query Plan It interprets and executes the query.

Description

Query DuckDB using Substrait Method for interpreting a Substrait BLOB plan as a DuckDB Query Plan It interprets and executes the query.

Usage

duckdb_prepare_substrait(conn, query, arrow = FALSE)

Arguments

conn

A DuckDB connection, created by dbConnect().

query

The Protobuf-encoded Substrait Query Plan. Qack!

arrow

Whether the result should be in Arrow format

Value

A DuckDB Query Result


Query DuckDB using Substrait Method for interpreting a Substrait JSON plan as a DuckDB Query Plan It interprets and executes the query.

Description

Query DuckDB using Substrait Method for interpreting a Substrait JSON plan as a DuckDB Query Plan It interprets and executes the query.

Usage

duckdb_prepare_substrait_json(conn, json, arrow = FALSE)

Arguments

conn

A DuckDB connection, created by dbConnect().

json

The Json Query Plan. Qack!

arrow

Whether the result should be in Arrow format

Value

A DuckDB Query Result


Reads a CSV file into DuckDB

Description

Directly reads a CSV file into DuckDB, tries to detect and create the correct schema for it. This usually is much faster than reading the data into R and writing it to DuckDB.

Usage

duckdb_read_csv(
  conn,
  name,
  files,
  header = TRUE,
  na.strings = "",
  nrow.check = 500,
  delim = ",",
  quote = "\"",
  col.names = NULL,
  lower.case.names = FALSE,
  sep = delim,
  transaction = TRUE,
  ...
)

Arguments

conn

A DuckDB connection, created by dbConnect().

name

The name for the virtual table that is registered or unregistered

files

One or more CSV file names, should all have the same structure though

header

Whether or not the CSV files have a separate header in the first line

na.strings

Which strings in the CSV files should be considered to be NULL

nrow.check

How many rows should be read from the CSV file to figure out data types

delim

Which field separator should be used

quote

Which quote character is used for columns in the CSV file

col.names

Override the detected or generated column names

lower.case.names

Transform column names to lower case

sep

Alias for delim for compatibility

transaction

Should a transaction be used for the entire operation

...

Passed on to read.csv()

Value

The number of rows in the resulted table, invisibly.

Examples

con <- dbConnect(duckdb())

data <- data.frame(a = 1:3, b = letters[1:3])
path <- tempfile(fileext = ".csv")

write.csv(data, path, row.names = FALSE)

duckdb_read_csv(con, "data", path)
dbReadTable(con, "data")

dbDisconnect(con)

Register a data frame as a virtual table

Description

duckdb_register() registers a data frame as a virtual table (view) in a DuckDB connection. No data is copied.

Usage

duckdb_register(conn, name, df, overwrite = FALSE, experimental = FALSE)

duckdb_unregister(conn, name)

Arguments

conn

A DuckDB connection, created by dbConnect().

name

The name for the virtual table that is registered or unregistered

df

A data.frame with the data for the virtual table

overwrite

Should an existing registration be overwritten?

experimental

Enable experimental optimizations

Details

duckdb_unregister() unregisters a previously registered data frame.

Value

These functions are called for their side effect.

Examples

con <- dbConnect(duckdb())

data <- data.frame(a = 1:3, b = letters[1:3])

duckdb_register(con, "data", data)
dbReadTable(con, "data")

duckdb_unregister(con, "data")

dbDisconnect(con)

Register an Arrow data source as a virtual table

Description

duckdb_register_arrow() registers an Arrow data source as a virtual table (view) in a DuckDB connection. No data is copied.

Usage

duckdb_register_arrow(conn, name, arrow_scannable, use_async = NULL)

duckdb_unregister_arrow(conn, name)

duckdb_list_arrow(conn)

Arguments

conn

A DuckDB connection, created by dbConnect().

name

The name for the virtual table that is registered or unregistered

arrow_scannable

A scannable Arrow-object

use_async

Switched to the asynchronous scanner. (deprecated)

Details

duckdb_unregister_arrow() unregisters a previously registered data frame.

Value

These functions are called for their side effect.