README

Name

Red Arrow DuckDB

Description

Red Arrow DuckDB is a library that provides Apache Arrow support to ruby-duckdb.

Install

gem install red-arrow-duckdb

Usage

Receive result as Apache Arrow data

require "arrow-duckdb"

DuckDB::Database.open do |db|
  db.connect do |connection|
    connection.query('CREATE TABLE users (id INTEGER, name VARCHAR(30))')

    connection.query("INSERT into users VALUES(1, 'Alice')")
    connection.query("INSERT into users VALUES(2, 'Bob')")
    connection.query("INSERT into users VALUES(3, 'Cathy')")

    result = connection.query("SELECT * FROM users", output: :arrow)
    puts(result.to_table)
    # 	id	name
    # 0	 1	Alice
    # 1	 2	Bob 
    # 2	 3	Cathy
  end
end

Use Apache Arrow data as input

require "arrow-duckdb"

users = Arrow::Table.new("id" => [1, 2, 3],
                         "name" => ["Alice", "Bob", "Cathy"])
DuckDB::Database.open do |db|
  db.connect do |connection|
    connection.register("users", users) do
      connection.query("SELECT * FROM users").each do |row|
        p row
        # ["1", "Alice"]
        # ["2", "Bob"]
        # ["3", "Cathy"]
      end
    end
  end
end

Filter Apache Arrow data by DuckDB

require "arrow-duckdb"

users = Arrow::Table.new("id" => [1, 2, 3],
                         "name" => ["Alice", "Bob", "Cathy"])
DuckDB::Database.open do |db|
  db.connect do |connection|
    filtered_users = connection.register("users", users) do
      result = connection.query("SELECT * FROM users WHERE id > ?",
                                1,
                                output: :arrow)
      result.to_table
    end
    puts(filtered_users)
    # 	id	name
    # 0	 2	Bob 
    # 1	 3	Cathy

    # Use filtered data again
    connection.register("filtered_users", filtered_users) do
      result = connection.query("SELECT * FROM filtered_users",
                                output: :arrow)
      puts(result.to_table)
      # 	id	name
      # 0	 2	Bob 
      # 1	 3	Cathy
    end
  end
end

Dependencies

• Red Arrow

• ruby-duckdb

Authors

• Sutou Kouhei <kou@clear-code.com>

License

Apache License 2.0. See doc/text/apache-2.0.txt for details.

(Sutou Kouhei has a right to change the license including contributed patches.)